Adding dri-devel and a few others because an i915 patch contributed to the regression.
On Mon, Jul 02, 2012 at 03:32:15PM +0100, Mel Gorman wrote:
On Mon, Jul 02, 2012 at 02:32:26AM -0400, Christoph Hellwig wrote:
It increases the CPU overhead (dirty_inode can be called up to 4 times per write(2) call, IIRC), so with limited numbers of threads/limited CPU power it will result in lower performance. Where you have lots of CPU power, there will be little difference in performance...
When I checked it it could only be called twice, and we'd already optimize away the second call. I'd defintively like to track down where the performance changes happend, at least to a major version but even better to a -rc or git commit.
By all means feel free to run the test yourself and run the bisection :)
It's rare but on this occasion the test machine is idle so I started an automated git bisection. As you know the milage with an automated bisect varies so it may or may not find the right commit. Test machine is sandy so http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-metadata-... is the report of interest. The script is doing a full search between v3.3 and v3.4 for a point where average files/sec for fsmark-single drops below 25000. I did not limit the search to fs/xfs on the off-chance that it is an apparently unrelated patch that caused the problem.
It was obvious very quickly that there were two distinct regression so I ran two bisections. One led to a XFS and the other led to an i915 patch that enables RC6 to reduce power usage.
[c999a223: xfs: introduce an allocation workqueue] [aa464191: drm/i915: enable plain RC6 on Sandy Bridge by default]
gdm was running on the machine so i915 would have been in use. In case it is of interest this is the log of the bisection. Lines beginning with # are notes I made and all other lines are from the bisection script. The second-last column is the files/sec recorded by fsmark.
# MARK v3.3..v3.4 Search for BAD files/sec -lt 28000 # BAD 16536 # GOOD 34757 Mon Jul 2 15:46:13 IST 2012 sandy xfsbisect 141124c02059eee9dbc5c86ea797b1ca888e77f7 37454 good Mon Jul 2 15:56:06 IST 2012 sandy xfsbisect 55a320308902f7a0746569ee57eeb3f254e6ed16 25192 bad Mon Jul 2 16:08:34 IST 2012 sandy xfsbisect 281b05392fc2cb26209b4d85abaf4889ab1991f3 38807 good Mon Jul 2 16:18:02 IST 2012 sandy xfsbisect a8364d5555b2030d093cde0f07951628e55454e1 37553 good Mon Jul 2 16:27:22 IST 2012 sandy xfsbisect d2a2fc18d98d8ee2dec1542efc7f47beec256144 36676 good Mon Jul 2 16:36:48 IST 2012 sandy xfsbisect 2e7580b0e75d771d93e24e681031a165b1d31071 37756 good Mon Jul 2 16:46:36 IST 2012 sandy xfsbisect 532bfc851a7475fb6a36c1e953aa395798a7cca7 25416 bad Mon Jul 2 16:56:10 IST 2012 sandy xfsbisect 0c9aac08261512d70d7d4817bd222abca8b6bdd6 38486 good Mon Jul 2 17:05:40 IST 2012 sandy xfsbisect 0fc9d1040313047edf6a39fd4d7c7defdca97c62 37970 good Mon Jul 2 17:16:01 IST 2012 sandy xfsbisect 5a5881cdeec2c019b5c9a307800218ee029f7f61 24493 bad Mon Jul 2 17:21:15 IST 2012 sandy xfsbisect f616137519feb17b849894fcbe634a021d3fa7db 24405 bad Mon Jul 2 17:26:16 IST 2012 sandy xfsbisect 5575acc7807595687288b3bbac15103f2a5462e1 37336 good Mon Jul 2 17:31:25 IST 2012 sandy xfsbisect c999a223c2f0d31c64ef7379814cea1378b2b800 24552 bad Mon Jul 2 17:36:34 IST 2012 sandy xfsbisect 1a1d772433d42aaff7315b3468fef5951604f5c6 36872 good # c999a223c2f0d31c64ef7379814cea1378b2b800 is the first bad commit # [c999a223: xfs: introduce an allocation workqueue] # # MARK c999a223c2f0d31c64ef7379814cea1378b2b800..v3.4 Search for BAD files/sec -lt 20000 # BAD 16536 # GOOD 24552 Mon Jul 2 17:48:39 IST 2012 sandy xfsbisect b2094ef840697bc8ca5d17a83b7e30fad5f1e9fa 37435 good Mon Jul 2 17:58:12 IST 2012 sandy xfsbisect d2a2fc18d98d8ee2dec1542efc7f47beec256144 38303 good Mon Jul 2 18:08:18 IST 2012 sandy xfsbisect 5d32c88f0b94061b3af2e3ade92422407282eb12 16718 bad Mon Jul 2 18:18:02 IST 2012 sandy xfsbisect 2f7fa1be66dce77608330c5eb918d6360b5525f2 24964 good Mon Jul 2 18:24:14 IST 2012 sandy xfsbisect 923f79743c76583ed4684e2c80c8da51a7268af3 24963 good Mon Jul 2 18:33:49 IST 2012 sandy xfsbisect b61c37f57988567c84359645f8202a7c84bc798a 24824 good Mon Jul 2 18:40:20 IST 2012 sandy xfsbisect 20a2a811602b16c42ce88bada3d52712cdfb988b 17155 bad Mon Jul 2 18:50:12 IST 2012 sandy xfsbisect 78fb72f7936c01d5b426c03a691eca082b03f2b9 38494 good Mon Jul 2 19:00:24 IST 2012 sandy xfsbisect e1a7eb08ee097e97e928062a242b0de5b2599a11 25033 good Mon Jul 2 19:10:24 IST 2012 sandy xfsbisect 97effadb65ed08809e1720c8d3ee80b73a93665c 16520 bad Mon Jul 2 19:16:16 IST 2012 sandy xfsbisect 25e341cfc33d94435472983825163e97fe370a6c 16748 bad Mon Jul 2 19:21:52 IST 2012 sandy xfsbisect 7dd4906586274f3945f2aeaaa5a33b451c3b4bba 24957 good Mon Jul 2 19:27:35 IST 2012 sandy xfsbisect aa46419186992e6b8b8010319f0ca7f40a0d13f5 17088 bad Mon Jul 2 19:32:54 IST 2012 sandy xfsbisect 83b7f9ac9126f0532ca34c14e4f0582c565c6b0d 25667 good # aa46419186992e6b8b8010319f0ca7f40a0d13f5 is the first bad commit # [aa464191: drm/i915: enable plain RC6 on Sandy Bridge by default]
I tested plain reverts of the patches individually and together and got the following results
FS-Mark Single Threaded 3.4.0 3.4.0 3.4.0 3.4.0-vanilla revert-aa464191 revert-c999a223 revert-both Files/s min 14176.40 ( 0.00%) 17830.60 (25.78%) 24186.70 (70.61%) 25108.00 (77.11%) Files/s mean 16783.35 ( 0.00%) 25029.69 (49.13%) 37513.72 (123.52%) 38169.97 (127.43%) Files/s stddev 1007.26 ( 0.00%) 2644.87 (162.58%) 5344.99 (430.65%) 5599.65 (455.93%) Files/s max 18475.40 ( 0.00%) 27966.10 (51.37%) 45564.60 (146.62%) 47918.10 (159.36%) Overhead min 593978.00 ( 0.00%) 386173.00 (34.99%) 253812.00 (57.27%) 247396.00 (58.35%) Overhead mean 637782.80 ( 0.00%) 429229.33 (32.70%) 322868.20 (49.38%) 287141.73 (54.98%) Overhead stddev 72440.72 ( 0.00%) 100056.96 (-38.12%) 175001.08 (-141.58%) 102018.14 (-40.83%) Overhead max 855637.00 ( 0.00%) 753541.00 (11.93%) 880531.00 (-2.91%) 637932.00 (25.44%) MMTests Statistics: duration Sys Time Running Test (seconds) 44.06 32.25 24.19 23.99 User+Sys Time Running Test (seconds) 50.19 36.35 27.24 26.7 Total Elapsed Time (seconds) 59.21 44.76 34.95 34.14
Individually reverting either patch makes a difference to both files/sec and overhead. Reverting both is not as dramatic as reverting each individual patch would indicate but it's still a major improvement.
On Mon, Jul 02, 2012 at 08:35:16PM +0100, Mel Gorman wrote:
Adding dri-devel and a few others because an i915 patch contributed to the regression.
On Mon, Jul 02, 2012 at 03:32:15PM +0100, Mel Gorman wrote:
On Mon, Jul 02, 2012 at 02:32:26AM -0400, Christoph Hellwig wrote:
It increases the CPU overhead (dirty_inode can be called up to 4 times per write(2) call, IIRC), so with limited numbers of threads/limited CPU power it will result in lower performance. Where you have lots of CPU power, there will be little difference in performance...
When I checked it it could only be called twice, and we'd already optimize away the second call. I'd defintively like to track down where the performance changes happend, at least to a major version but even better to a -rc or git commit.
By all means feel free to run the test yourself and run the bisection :)
It's rare but on this occasion the test machine is idle so I started an automated git bisection. As you know the milage with an automated bisect varies so it may or may not find the right commit. Test machine is sandy so http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-metadata-... is the report of interest. The script is doing a full search between v3.3 and v3.4 for a point where average files/sec for fsmark-single drops below 25000. I did not limit the search to fs/xfs on the off-chance that it is an apparently unrelated patch that caused the problem.
It was obvious very quickly that there were two distinct regression so I ran two bisections. One led to a XFS and the other led to an i915 patch that enables RC6 to reduce power usage.
[aa464191: drm/i915: enable plain RC6 on Sandy Bridge by default]
Doesn't seem to be the major cause of the regression. By itself, it has impact, but the majority comes from the XFS change...
[c999a223: xfs: introduce an allocation workqueue]
Which indicates that there is workqueue scheduling issues, I think. The same amount of work is being done, but half of it is being pushed off into a workqueue to avoid stack overflow issues (*). I tested the above patch in anger on an 8p machine, similar to the machine you saw no regressions on, but the workload didn't drive it to being completely CPU bound (only about 90%) so the allocation work was probably always scheduled quickly.
How many worker threads have been spawned on these machines that are showing the regression? What is the context switch rate on the machines whenteh test is running? Can you run latencytop to see if there is excessive starvation/wait times for allocation completion? A pert top profile comparison might be informative, too...
(*) The stack usage below submit_bio() can be more than 5k (DM, MD, SCSI, driver, memory allocation), so it's really not safe to do allocation anywhere below about 3k of kernel stack being used. e.g. on a relatively trivial storage setup without the above commit:
[142296.384921] flush-253:4 used greatest stack depth: 360 bytes left
Fundamentally, 8k stacks on x86-64 are too small for our increasingly complex storage layers and the 100+ function deep call chains that occur.
Cheers,
Dave.
On Tue, Jul 03, 2012 at 10:19:28AM +1000, Dave Chinner wrote:
On Mon, Jul 02, 2012 at 08:35:16PM +0100, Mel Gorman wrote:
Adding dri-devel and a few others because an i915 patch contributed to the regression.
On Mon, Jul 02, 2012 at 03:32:15PM +0100, Mel Gorman wrote:
On Mon, Jul 02, 2012 at 02:32:26AM -0400, Christoph Hellwig wrote:
It increases the CPU overhead (dirty_inode can be called up to 4 times per write(2) call, IIRC), so with limited numbers of threads/limited CPU power it will result in lower performance. Where you have lots of CPU power, there will be little difference in performance...
When I checked it it could only be called twice, and we'd already optimize away the second call. I'd defintively like to track down where the performance changes happend, at least to a major version but even better to a -rc or git commit.
By all means feel free to run the test yourself and run the bisection :)
It's rare but on this occasion the test machine is idle so I started an automated git bisection. As you know the milage with an automated bisect varies so it may or may not find the right commit. Test machine is sandy so http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-metadata-... is the report of interest. The script is doing a full search between v3.3 and v3.4 for a point where average files/sec for fsmark-single drops below 25000. I did not limit the search to fs/xfs on the off-chance that it is an apparently unrelated patch that caused the problem.
It was obvious very quickly that there were two distinct regression so I ran two bisections. One led to a XFS and the other led to an i915 patch that enables RC6 to reduce power usage.
[aa464191: drm/i915: enable plain RC6 on Sandy Bridge by default]
Doesn't seem to be the major cause of the regression. By itself, it has impact, but the majority comes from the XFS change...
The fact it has an impact at all is weird but lets see what the DRI folks think about it.
[c999a223: xfs: introduce an allocation workqueue]
Which indicates that there is workqueue scheduling issues, I think. The same amount of work is being done, but half of it is being pushed off into a workqueue to avoid stack overflow issues (*). I tested the above patch in anger on an 8p machine, similar to the machine you saw no regressions on, but the workload didn't drive it to being completely CPU bound (only about 90%) so the allocation work was probably always scheduled quickly.
What test were you using?
How many worker threads have been spawned on these machines that are showing the regression?
20 or 21 generally. An example list as spotted by top looks like
kworker/0:0 kworker/0:1 kworker/0:2 kworker/1:0 kworker/1:1 kworker/1:2 kworker/2:0 kworker/2:1 kworker/2:2 kworker/3:0 kworker/3:1 kworker/3:2 kworker/4:0 kworker/4:1 kworker/5:0 kworker/5:1 kworker/6:0 kworker/6:1 kworker/6:2 kworker/7:0 kworker/7:1
There were 8 unbound workers.
What is the context switch rate on the machines whenteh test is running?
This is vmstat from a vanilla kernel. The actual vmstat is after the --. The information before that is recorded by mmtests to try and detect if there was jitter in the vmstat output. It's showing that there is little or no jitter in this test.
VANILLA 1341306582.6713 1.8109 1.8109 -- 0 0 0 16050784 11448 104056 0 0 376 0 209 526 0 0 99 1 0 1341306584.6715 3.8112 2.0003 -- 1 0 0 16050628 11448 104064 0 0 0 0 121 608 0 0 100 0 0 1341306586.6718 5.8114 2.0003 -- 0 0 0 16047432 11460 104288 0 0 102 45 227 999 0 0 99 1 0 1341306588.6721 7.8117 2.0003 -- 1 0 0 16046944 11460 104292 0 0 0 0 120 663 0 0 100 0 0 1341306590.6723 9.8119 2.0002 -- 0 2 0 16045788 11476 104296 0 0 12 40 190 754 0 0 99 0 0 1341306592.6725 11.8121 2.0002 -- 0 1 0 15990236 12600 141724 0 0 19054 30 1400 2937 2 1 88 9 0 1341306594.6727 13.8124 2.0002 -- 1 0 0 15907628 12600 186360 0 0 1653 0 3117 6406 2 9 88 1 0 1341306596.6730 15.8127 2.0003 -- 0 0 0 15825964 12608 226636 0 0 15 11024 3073 6350 2 9 89 0 0 1341306598.6733 17.8130 2.0003 -- 1 0 0 15730420 12608 271632 0 0 0 3072 3461 7179 2 10 88 0 0 1341306600.6736 19.8132 2.0003 -- 1 0 0 15686200 12608 310816 0 0 0 12416 3093 6198 2 9 89 0 0 1341306602.6738 21.8135 2.0003 -- 2 0 0 15593588 12616 354928 0 0 0 32 3482 7146 2 11 87 0 0 1341306604.6741 23.8138 2.0003 -- 2 0 0 15562032 12616 393772 0 0 0 12288 3129 6330 2 10 89 0 0 1341306606.6744 25.8140 2.0002 -- 1 0 0 15458316 12624 438004 0 0 0 26 3471 7107 2 11 87 0 0 1341306608.6746 27.8142 2.0002 -- 1 0 0 15432024 12624 474244 0 0 0 12416 3011 6017 1 10 89 0 0 1341306610.6749 29.8145 2.0003 -- 2 0 0 15343280 12624 517696 0 0 0 24 3393 6826 2 11 87 0 0 1341306612.6751 31.8148 2.0002 -- 1 0 0 15311136 12632 551816 0 0 0 16502 2818 5653 2 9 88 1 0 1341306614.6754 33.8151 2.0003 -- 1 0 0 15220648 12632 594936 0 0 0 3584 3451 6779 2 11 87 0 0 1341306616.6755 35.8152 2.0001 -- 4 0 0 15221252 12632 649296 0 0 0 38559 4846 8709 2 15 78 6 0 1341306618.6758 37.8155 2.0003 -- 1 0 0 15177724 12640 668476 0 0 20 40679 2204 4067 1 5 89 5 0 1341306620.6761 39.8158 2.0003 -- 1 0 0 15090204 12640 711752 0 0 0 0 3316 6788 2 11 88 0 0 1341306622.6764 41.8160 2.0003 -- 1 0 0 15005356 12640 748532 0 0 0 12288 3073 6132 2 10 89 0 0 1341306624.6766 43.8163 2.0002 -- 2 0 0 14913088 12648 791952 0 0 0 28 3408 6806 2 11 87 0 0 1341306626.6769 45.8166 2.0003 -- 1 0 0 14891512 12648 826328 0 0 0 12420 2906 5710 1 9 90 0 0 1341306628.6772 47.8168 2.0003 -- 1 0 0 14794316 12656 868936 0 0 0 26 3367 6798 2 11 87 0 0 1341306630.6774 49.8171 2.0003 -- 1 0 0 14769188 12656 905016 0 0 30 12324 3029 5876 2 10 89 0 0 1341306632.6777 51.8173 2.0002 -- 1 0 0 14679544 12656 947712 0 0 0 0 3399 6868 2 11 87 0 0 1341306634.6780 53.8176 2.0003 -- 1 0 0 14646156 12664 982032 0 0 0 14658 2987 5761 1 10 89 0 0 1341306636.6782 55.8179 2.0003 -- 1 0 0 14560504 12664 1023816 0 0 0 4404 3454 6876 2 11 87 0 0 1341306638.6783 57.8180 2.0001 -- 2 0 0 14533384 12664 1056812 0 0 0 15810 3002 5581 1 10 89 0 0 1341306640.6785 59.8182 2.0002 -- 1 0 0 14593332 12672 1027392 0 0 0 31790 3504 1811 1 13 78 8 0 1341306642.6787 61.8183 2.0001 -- 1 0 0 14686968 12672 1007604 0 0 0 14621 2434 1248 1 10 89 0 0 1341306644.6789 63.8185 2.0002 -- 1 1 0 15042476 12680 788104 0 0 0 36564 2809 1484 1 12 86 1 0 1341306646.6790 65.8187 2.0002 -- 1 0 0 15128292 12680 757948 0 0 0 26395 3050 1313 1 13 86 1 0 1341306648.6792 67.8189 2.0002 -- 1 0 0 15160036 12680 727964 0 0 0 5463 2752 910 1 12 87 0 0 1341306650.6795 69.8192 2.0003 -- 0 0 0 15633256 12688 332572 0 0 1156 12308 2117 2346 1 7 91 1 0 1341306652.6797 71.8194 2.0002 -- 0 0 0 15633892 12688 332652 0 0 0 0 224 758 0 0 100 0 0 1341306654.6800 73.8197 2.0003 -- 0 0 0 15633900 12688 332524 0 0 0 0 231 1009 0 0 100 0 0 1341306656.6803 75.8199 2.0003 -- 0 0 0 15637436 12696 332504 0 0 0 38 266 713 0 0 99 0 0 1341306658.6805 77.8202 2.0003 -- 0 0 0 15654180 12696 332352 0 0 0 0 270 821 0 0 100 0 0
REVERT-XFS 1341307733.8702 1.7941 1.7941 -- 0 0 0 16050640 12036 103996 0 0 372 0 216 752 0 0 99 1 0 1341307735.8704 3.7944 2.0002 -- 0 0 0 16050864 12036 104028 0 0 0 0 132 857 0 0 100 0 0 1341307737.8707 5.7946 2.0002 -- 0 0 0 16047492 12048 104252 0 0 102 37 255 938 0 0 99 1 0 1341307739.8709 7.7949 2.0003 -- 0 0 0 16047600 12072 104324 0 0 32 2 129 658 0 0 100 0 0 1341307741.8712 9.7951 2.0002 -- 1 1 0 16046676 12080 104328 0 0 0 32 165 729 0 0 100 0 0 1341307743.8714 11.7954 2.0003 -- 0 1 0 15990840 13216 142612 0 0 19422 30 1467 3015 2 1 89 8 0 1341307745.8717 13.7956 2.0002 -- 0 0 0 15825496 13216 226396 0 0 1310 11214 2217 1348 2 8 89 1 0 1341307747.8717 15.7957 2.0001 -- 1 0 0 15677816 13224 314672 0 0 4 15294 2307 1173 2 9 89 0 0 1341307749.8719 17.7959 2.0002 -- 1 0 0 15524372 13224 409728 0 0 0 12288 2466 888 1 10 89 0 0 1341307751.8721 19.7960 2.0002 -- 1 0 0 15368424 13224 502552 0 0 0 12416 2312 878 1 10 89 0 0 1341307753.8722 21.7962 2.0002 -- 1 0 0 15225216 13232 593092 0 0 0 12448 2539 1380 1 10 88 0 0 1341307755.8724 23.7963 2.0002 -- 2 0 0 15163712 13232 664768 0 0 0 32160 2184 1177 1 8 90 0 0 1341307757.8727 25.7967 2.0003 -- 1 0 0 14973888 13240 755080 0 0 0 12316 2482 1219 1 10 89 0 0 1341307759.8728 27.7968 2.0001 -- 1 0 0 14883580 13240 840036 0 0 0 44471 2711 1234 2 10 88 0 0 1341307761.8730 29.7970 2.0002 -- 1 0 0 14800304 13240 920504 0 0 0 42554 2571 1050 1 10 89 0 0 1341307763.8734 31.7973 2.0003 -- 0 0 0 14642504 13248 995004 0 0 0 3232 2276 1081 1 8 90 0 0 1341307765.8737 33.7976 2.0003 -- 1 0 0 14545072 13248 1052536 0 0 0 18688 2628 1114 1 9 89 0 0 1341307767.8739 35.7979 2.0003 -- 1 0 0 14783848 13248 926824 0 0 0 59559 2409 1308 0 10 89 1 0 1341307769.8740 37.7980 2.0001 -- 2 0 0 14854800 13256 896832 0 0 0 9172 2419 1004 1 10 89 1 0 1341307771.8742 39.7981 2.0002 -- 2 0 0 14835084 13256 875612 0 0 0 12288 2524 812 0 11 89 0 0 1341307773.8743 41.7983 2.0002 -- 2 0 0 15126252 13256 745844 0 0 0 10297 2714 1163 1 12 88 0 0 1341307775.8745 43.7985 2.0002 -- 1 0 0 15108800 13264 724544 0 0 0 12316 2499 931 1 11 88 0 0 1341307777.8746 45.7986 2.0001 -- 2 0 0 15226236 13264 694580 0 0 0 12416 2700 1194 1 12 88 0 0 1341307779.8750 47.7989 2.0003 -- 1 0 0 15697632 13264 300716 0 0 1156 0 934 1701 0 2 96 1 0 1341307781.8752 49.7992 2.0003 -- 0 0 0 15697508 13272 300720 0 0 0 66 166 641 0 0 100 0 0 1341307783.8755 51.7995 2.0003 -- 0 0 0 15699008 13272 300524 0 0 0 0 248 865 0 0 100 0 0 1341307785.8758 53.7997 2.0003 -- 0 0 0 15702452 13272 300520 0 0 0 0 285 960 0 0 99 0 0 1341307787.8760 55.7999 2.0002 -- 0 0 0 15719404 13280 300436 0 0 0 26 136 590 0 0 99 0 0
Vanilla average context switch rate 4278.53 Revert average context switch rate 1095
Can you run latencytop to see if there is excessive starvation/wait times for allocation completion?
I'm not sure what format you are looking for. latencytop is shit for capturing information throughout a test and it does not easily allow you to record a snapshot of a test. You can record all the console output of course but that's a complete mess. I tried capturing /proc/latency_stats over time instead because that can be trivially sorted on a system-wide basis but as I write this I find that latency_stats was bust. It was just spitting out
Latency Top version : v0.1
and nothing else. Either latency_stats is broken or my config is. Not sure which it is right now and won't get enough time on this today to pinpoint it.
A pert top profile comparison might be informative, too...
I'm not sure if this is what you really wanted. I thought an oprofile or perf report would have made more sense but I recorded perf top over time anyway and it's at the end of the mail. The timestamp information is poor because the perf top information was buffered so it would receive a bunch of updates at once. Each sample should be roughly 2 seconds apart. This buffering can be dealt with, I just failed to do it in advance and I do not think it's necessary to rerun the tests for it.
(*) The stack usage below submit_bio() can be more than 5k (DM, MD, SCSI, driver, memory allocation), so it's really not safe to do allocation anywhere below about 3k of kernel stack being used. e.g. on a relatively trivial storage setup without the above commit:
[142296.384921] flush-253:4 used greatest stack depth: 360 bytes left
Fundamentally, 8k stacks on x86-64 are too small for our increasingly complex storage layers and the 100+ function deep call chains that occur.
I understand the patches motivation. For these tests I'm being deliberately a bit of a dummy and just capturing information. This might allow me to actually get through all the results and identify some of the problems and spread them around a bit. Either that or I need to clone myself a few times to tackle each of the problems in a reasonable timeframe :)
For just these XFS tests I've uploaded a tarball of the logs to http://www.csn.ul.ie/~mel/postings/xfsbisect-20120703/xfsbisect-logs.tar.gz
For results with no monitor you can find them somewhere like this
default/no-monitor/sandy/fsmark-single-3.4.0-vanilla/noprofile/fsmark.log
Results with monitors attached are in run-monitor. You can read the iostat logs for example from
default/run-monitor/sandy/iostat-3.4.0-vanilla-fsmark-single
Some of the monitor logs are gzipped.
This is perf top over time for the vanilla kernel
time: 1341306570
time: 1341306579 PerfTop: 1 irqs/sec kernel: 0.0% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
61.85% [kernel] [k] __rmqueue 38.15% libc-2.11.3.so [.] _IO_vfscanf
time: 1341306579 PerfTop: 3 irqs/sec kernel:66.7% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
19.88% [kernel] [k] _raw_spin_lock_irqsave 17.14% [kernel] [k] __rmqueue 16.96% [kernel] [k] format_decode 15.37% libc-2.11.3.so [.] __tzfile_compute 13.55% [kernel] [k] copy_user_generic_string 10.57% libc-2.11.3.so [.] _IO_vfscanf 6.53% [kernel] [k] find_first_bit
time: 1341306579 PerfTop: 0 irqs/sec kernel:-nan% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
17.51% [kernel] [k] _raw_spin_lock_irqsave 15.10% [kernel] [k] __rmqueue 14.94% [kernel] [k] format_decode 13.54% libc-2.11.3.so [.] __tzfile_compute 11.94% [kernel] [k] copy_user_generic_string 11.90% [kernel] [k] _raw_spin_lock 9.31% libc-2.11.3.so [.] _IO_vfscanf 5.75% [kernel] [k] find_first_bit
time: 1341306579 PerfTop: 41 irqs/sec kernel:58.5% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
13.62% [kernel] [k] _raw_spin_lock_irqsave 11.02% [kernel] [k] __rmqueue 10.91% [kernel] [k] format_decode 9.89% libc-2.11.3.so [.] __tzfile_compute 8.72% [kernel] [k] copy_user_generic_string 8.69% [kernel] [k] _raw_spin_lock 7.15% libc-2.11.3.so [.] _IO_vfscanf 4.20% [kernel] [k] find_first_bit 1.47% libc-2.11.3.so [.] __strcmp_sse42 1.37% libc-2.11.3.so [.] __strchr_sse42 1.19% sed [.] 0x0000000000009f7d 0.90% libc-2.11.3.so [.] vfprintf 0.84% [kernel] [k] hrtimer_interrupt 0.84% libc-2.11.3.so [.] re_string_realloc_buffers 0.76% [kernel] [k] enqueue_entity 0.66% [kernel] [k] __switch_to 0.65% libc-2.11.3.so [.] _IO_default_xsputn 0.62% [kernel] [k] do_vfs_ioctl 0.59% [kernel] [k] perf_event_mmap_event 0.56% gzip [.] 0x0000000000007b96 0.55% libc-2.11.3.so [.] bsearch
time: 1341306579 PerfTop: 35 irqs/sec kernel:62.9% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.50% [kernel] [k] _raw_spin_lock_irqsave 9.22% [kernel] [k] __rmqueue 9.13% [kernel] [k] format_decode 8.27% libc-2.11.3.so [.] __tzfile_compute 7.92% [kernel] [k] copy_user_generic_string 7.74% [kernel] [k] _raw_spin_lock 6.21% libc-2.11.3.so [.] _IO_vfscanf 3.51% [kernel] [k] find_first_bit 1.44% gzip [.] 0x0000000000007b96 1.23% libc-2.11.3.so [.] __strcmp_sse42 1.15% libc-2.11.3.so [.] __strchr_sse42 1.06% libc-2.11.3.so [.] vfprintf 0.99% sed [.] 0x0000000000009f7d 0.92% [unknown] [.] 0x00007f84a7766b99 0.70% [kernel] [k] hrtimer_interrupt 0.70% libc-2.11.3.so [.] re_string_realloc_buffers 0.64% [kernel] [k] enqueue_entity 0.58% libtcl8.5.so [.] 0x000000000006fe86 0.55% [kernel] [k] __switch_to 0.54% libc-2.11.3.so [.] _IO_default_xsputn 0.53% [kernel] [k] __d_lookup_rcu
time: 1341306585 PerfTop: 100 irqs/sec kernel:59.0% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
8.61% [kernel] [k] _raw_spin_lock_irqsave 5.92% [kernel] [k] __rmqueue 5.86% [kernel] [k] format_decode 5.31% libc-2.11.3.so [.] __tzfile_compute 5.30% [kernel] [k] copy_user_generic_string 5.27% [kernel] [k] _raw_spin_lock 3.99% libc-2.11.3.so [.] _IO_vfscanf 2.45% [unknown] [.] 0x00007f84a7766b99 2.26% [kernel] [k] find_first_bit 1.68% [kernel] [k] page_fault 1.45% libc-2.11.3.so [.] _int_malloc 1.28% gzip [.] 0x0000000000007b96 1.13% libc-2.11.3.so [.] vfprintf 1.06% libc-2.11.3.so [.] __strchr_sse42 1.02% perl [.] 0x0000000000044505 0.79% libc-2.11.3.so [.] __strcmp_sse42 0.79% [kernel] [k] do_task_stat 0.77% [kernel] [k] zap_pte_range 0.72% libc-2.11.3.so [.] __gconv_transform_utf8_internal 0.70% libc-2.11.3.so [.] malloc 0.70% libc-2.11.3.so [.] __mbrtowc
time: 1341306585 PerfTop: 19 irqs/sec kernel:78.9% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
7.97% [kernel] [k] _raw_spin_lock_irqsave 5.48% [kernel] [k] __rmqueue 5.43% [kernel] [k] format_decode 5.24% [kernel] [k] copy_user_generic_string 5.18% [kernel] [k] _raw_spin_lock 4.92% libc-2.11.3.so [.] __tzfile_compute 4.25% libc-2.11.3.so [.] _IO_vfscanf 2.33% [unknown] [.] 0x00007f84a7766b99 2.12% [kernel] [k] page_fault 2.09% [kernel] [k] find_first_bit 1.34% libc-2.11.3.so [.] _int_malloc 1.19% gzip [.] 0x0000000000007b96 1.05% libc-2.11.3.so [.] vfprintf 0.98% libc-2.11.3.so [.] __strchr_sse42 0.94% perl [.] 0x0000000000044505 0.94% libc-2.11.3.so [.] _dl_addr 0.91% [kernel] [k] zap_pte_range 0.74% [kernel] [k] s_show 0.73% libc-2.11.3.so [.] __strcmp_sse42 0.73% [kernel] [k] do_task_stat 0.67% libc-2.11.3.so [.] __gconv_transform_utf8_internal
time: 1341306585 PerfTop: 38 irqs/sec kernel:68.4% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
7.64% [kernel] [k] _raw_spin_lock_irqsave 4.89% [kernel] [k] _raw_spin_lock 4.77% [kernel] [k] __rmqueue 4.72% [kernel] [k] format_decode 4.56% [kernel] [k] copy_user_generic_string 4.53% libc-2.11.3.so [.] _IO_vfscanf 4.28% libc-2.11.3.so [.] __tzfile_compute 2.52% [unknown] [.] 0x00007f84a7766b99 no symbols found in /bin/sort, maybe install a debug package? 2.10% [kernel] [k] page_fault 1.82% [kernel] [k] find_first_bit 1.31% libc-2.11.3.so [.] _int_malloc 1.14% libc-2.11.3.so [.] vfprintf 1.08% libc-2.11.3.so [.] _dl_addr 1.07% [kernel] [k] s_show 1.05% libc-2.11.3.so [.] __strchr_sse42 1.03% gzip [.] 0x0000000000007b96 0.82% [kernel] [k] do_task_stat 0.82% perl [.] 0x0000000000044505 0.79% [kernel] [k] zap_pte_range 0.70% [kernel] [k] seq_put_decimal_ull 0.69% [kernel] [k] find_busiest_group
time: 1341306591 PerfTop: 66 irqs/sec kernel:59.1% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
6.52% [kernel] [k] _raw_spin_lock_irqsave 4.11% libc-2.11.3.so [.] _IO_vfscanf 3.91% [kernel] [k] _raw_spin_lock 3.50% [kernel] [k] copy_user_generic_string 3.41% [kernel] [k] __rmqueue 3.38% [kernel] [k] format_decode 3.06% libc-2.11.3.so [.] __tzfile_compute 2.90% [unknown] [.] 0x00007f84a7766b99 2.30% [kernel] [k] page_fault 2.20% perl [.] 0x0000000000044505 1.83% libc-2.11.3.so [.] vfprintf 1.61% libc-2.11.3.so [.] _int_malloc 1.30% [kernel] [k] find_first_bit 1.22% libc-2.11.3.so [.] _dl_addr 1.19% libc-2.11.3.so [.] __gconv_transform_utf8_internal 1.10% libc-2.11.3.so [.] __strchr_sse42 1.01% [kernel] [k] zap_pte_range 0.99% [kernel] [k] s_show 0.98% [kernel] [k] __percpu_counter_add 0.86% [kernel] [k] __strnlen_user 0.75% ld-2.11.3.so [.] do_lookup_x
time: 1341306591 PerfTop: 39 irqs/sec kernel:69.2% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
6.26% [kernel] [k] _raw_spin_lock_irqsave 4.05% [kernel] [k] _raw_spin_lock 3.86% libc-2.11.3.so [.] _IO_vfscanf 3.21% [kernel] [k] copy_user_generic_string 3.03% [kernel] [k] __rmqueue 3.00% [kernel] [k] format_decode 2.93% [unknown] [.] 0x00007f84a7766b99 2.72% libc-2.11.3.so [.] __tzfile_compute 2.20% [kernel] [k] page_fault 1.96% perl [.] 0x0000000000044505 1.77% libc-2.11.3.so [.] vfprintf 1.43% libc-2.11.3.so [.] _int_malloc 1.16% [kernel] [k] find_first_bit 1.09% libc-2.11.3.so [.] _dl_addr 1.06% libc-2.11.3.so [.] __gconv_transform_utf8_internal 1.02% [kernel] [k] s_show 0.98% libc-2.11.3.so [.] __strchr_sse42 0.93% gzip [.] 0x0000000000007b96 0.90% [kernel] [k] zap_pte_range 0.87% [kernel] [k] __percpu_counter_add 0.76% [kernel] [k] __strnlen_user
time: 1341306591 PerfTop: 185 irqs/sec kernel:70.8% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
4.81% [kernel] [k] _raw_spin_lock_irqsave 3.60% [unknown] [.] 0x00007f84a7766b99 3.10% [kernel] [k] _raw_spin_lock 3.04% [kernel] [k] page_fault 2.66% libc-2.11.3.so [.] _IO_vfscanf 2.14% [kernel] [k] copy_user_generic_string 2.11% [kernel] [k] format_decode 1.96% [kernel] [k] __rmqueue 1.86% libc-2.11.3.so [.] _dl_addr 1.76% libc-2.11.3.so [.] __tzfile_compute 1.26% perl [.] 0x0000000000044505 1.19% libc-2.11.3.so [.] __mbrtowc 1.14% libc-2.11.3.so [.] vfprintf 1.12% libc-2.11.3.so [.] _int_malloc 1.09% gzip [.] 0x0000000000007b96 0.95% libc-2.11.3.so [.] __gconv_transform_utf8_internal 0.88% [kernel] [k] _raw_spin_unlock_irqrestore 0.87% [kernel] [k] __strnlen_user 0.82% [kernel] [k] clear_page_c 0.77% [kernel] [k] __schedule 0.76% [kernel] [k] find_get_page
time: 1341306595 PerfTop: 385 irqs/sec kernel:48.8% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
27.20% cc1 [.] 0x0000000000210978 3.01% [unknown] [.] 0x00007f84a7766b99 2.18% [kernel] [k] page_fault 1.96% libbfd-2.21.so [.] 0x00000000000b9cdd 1.95% [kernel] [k] _raw_spin_lock_irqsave 1.91% ld.bfd [.] 0x000000000000e3b9 1.85% [kernel] [k] _raw_spin_lock 1.31% [kernel] [k] copy_user_generic_string 1.20% libbfd-2.21.so [.] bfd_hash_lookup 1.10% libc-2.11.3.so [.] __strcmp_sse42 0.93% libc-2.11.3.so [.] _IO_vfscanf 0.85% [kernel] [k] _raw_spin_unlock_irqrestore 0.82% libc-2.11.3.so [.] _int_malloc 0.80% [kernel] [k] __rmqueue 0.79% [kernel] [k] kmem_cache_alloc 0.74% [kernel] [k] format_decode 0.71% libc-2.11.3.so [.] _dl_addr 0.62% libbfd-2.21.so [.] _bfd_final_link_relocate 0.61% libc-2.11.3.so [.] __tzfile_compute 0.61% libc-2.11.3.so [.] vfprintf 0.59% [kernel] [k] find_busiest_group
time: 1341306595 PerfTop: 1451 irqs/sec kernel:87.3% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
9.75% cc1 [.] 0x0000000000210978 8.81% [unknown] [.] 0x00007f84a7766b99 4.62% [kernel] [k] page_fault 3.61% [kernel] [k] _raw_spin_lock 2.67% [kernel] [k] memcpy 2.03% [kernel] [k] _raw_spin_lock_irqsave 2.00% [kernel] [k] kmem_cache_alloc 1.64% [xfs] [k] _xfs_buf_find 1.31% [kernel] [k] _raw_spin_unlock_irqrestore 1.16% [kernel] [k] kmem_cache_free 1.15% [xfs] [k] xfs_next_bit 0.98% [kernel] [k] __d_lookup 0.89% [xfs] [k] xfs_da_do_buf 0.83% [kernel] [k] memset 0.80% [xfs] [k] xfs_dir2_node_addname_int 0.79% [kernel] [k] link_path_walk 0.76% [xfs] [k] xfs_buf_item_size no symbols found in /usr/bin/tee, maybe install a debug package? no symbols found in /bin/date, maybe install a debug package? 0.73% [xfs] [k] xfs_buf_offset 0.71% [kernel] [k] __kmalloc 0.70% [kernel] [k] kfree 0.70% libbfd-2.21.so [.] 0x00000000000b9cdd
time: 1341306601 PerfTop: 1267 irqs/sec kernel:85.2% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
10.81% [unknown] [.] 0x00007f84a7766b99 5.98% cc1 [.] 0x0000000000210978 5.20% [kernel] [k] page_fault 3.54% [kernel] [k] _raw_spin_lock 3.37% [kernel] [k] memcpy 2.03% [kernel] [k] kmem_cache_alloc 1.91% [kernel] [k] _raw_spin_lock_irqsave 1.75% [xfs] [k] _xfs_buf_find 1.35% [kernel] [k] _raw_spin_unlock_irqrestore 1.28% [xfs] [k] xfs_next_bit 1.14% [kernel] [k] kmem_cache_free 1.13% [kernel] [k] __kmalloc 1.12% [kernel] [k] __d_lookup 0.97% [xfs] [k] xfs_dir2_node_addname_int 0.96% [xfs] [k] xfs_buf_offset 0.95% [kernel] [k] memset 0.91% [kernel] [k] link_path_walk 0.88% [xfs] [k] xfs_da_do_buf 0.85% [kernel] [k] kfree 0.84% [xfs] [k] xfs_buf_item_size 0.74% [xfs] [k] xfs_btree_lookup
time: 1341306601 PerfTop: 1487 irqs/sec kernel:85.3% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.84% [unknown] [.] 0x00007f84a7766b99 5.15% [kernel] [k] page_fault 3.93% cc1 [.] 0x0000000000210978 3.76% [kernel] [k] _raw_spin_lock 3.50% [kernel] [k] memcpy 2.13% [kernel] [k] kmem_cache_alloc 1.91% [xfs] [k] _xfs_buf_find 1.79% [kernel] [k] _raw_spin_lock_irqsave 1.52% [kernel] [k] __kmalloc 1.33% [kernel] [k] kmem_cache_free 1.32% [kernel] [k] _raw_spin_unlock_irqrestore 1.29% [kernel] [k] __d_lookup 1.27% [xfs] [k] xfs_next_bit 1.11% [kernel] [k] link_path_walk 1.01% [xfs] [k] xfs_buf_offset 1.00% [xfs] [k] xfs_dir2_node_addname_int 0.98% [xfs] [k] xfs_da_do_buf 0.97% [kernel] [k] kfree 0.96% [kernel] [k] memset 0.84% [xfs] [k] xfs_btree_lookup 0.82% [xfs] [k] xfs_buf_item_format
time: 1341306601 PerfTop: 1291 irqs/sec kernel:85.9% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
12.21% [unknown] [.] 0x00007f84a7766b99 5.18% [kernel] [k] page_fault 3.83% [kernel] [k] _raw_spin_lock 3.67% [kernel] [k] memcpy 2.92% cc1 [.] 0x0000000000210978 2.28% [kernel] [k] kmem_cache_alloc 2.18% [xfs] [k] _xfs_buf_find 1.66% [kernel] [k] _raw_spin_lock_irqsave 1.56% [kernel] [k] __kmalloc 1.43% [kernel] [k] __d_lookup 1.43% [kernel] [k] _raw_spin_unlock_irqrestore 1.40% [kernel] [k] kmem_cache_free 1.29% [xfs] [k] xfs_next_bit 1.13% [xfs] [k] xfs_buf_offset 1.07% [kernel] [k] link_path_walk 1.04% [xfs] [k] xfs_da_do_buf 1.01% [kernel] [k] memset 1.01% [kernel] [k] kfree 1.00% [xfs] [k] xfs_dir2_node_addname_int 0.87% [xfs] [k] xfs_buf_item_size 0.84% [xfs] [k] xfs_btree_lookup
time: 1341306607 PerfTop: 1435 irqs/sec kernel:87.9% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
12.06% [unknown] [.] 0x00007f84a7766b99 5.40% [kernel] [k] page_fault 3.88% [kernel] [k] _raw_spin_lock 3.83% [kernel] [k] memcpy 2.41% [xfs] [k] _xfs_buf_find 2.35% [kernel] [k] kmem_cache_alloc 2.19% cc1 [.] 0x0000000000210978 1.68% [kernel] [k] _raw_spin_lock_irqsave 1.55% [kernel] [k] __kmalloc 1.48% [kernel] [k] __d_lookup 1.43% [kernel] [k] kmem_cache_free 1.42% [kernel] [k] _raw_spin_unlock_irqrestore 1.37% [xfs] [k] xfs_next_bit 1.27% [xfs] [k] xfs_buf_offset 1.12% [kernel] [k] link_path_walk 1.09% [kernel] [k] kfree 1.08% [kernel] [k] memset 1.04% [xfs] [k] xfs_da_do_buf 0.99% [xfs] [k] xfs_dir2_node_addname_int 0.92% [xfs] [k] xfs_buf_item_size 0.89% [xfs] [k] xfs_btree_lookup
time: 1341306607 PerfTop: 1281 irqs/sec kernel:87.0% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
12.00% [unknown] [.] 0x00007f84a7766b99 5.44% [kernel] [k] page_fault 4.04% [kernel] [k] _raw_spin_lock 3.94% [kernel] [k] memcpy 2.51% [xfs] [k] _xfs_buf_find 2.32% [kernel] [k] kmem_cache_alloc 1.75% cc1 [.] 0x0000000000210978 1.66% [kernel] [k] _raw_spin_lock_irqsave 1.58% [kernel] [k] __d_lookup 1.56% [kernel] [k] __kmalloc 1.46% [xfs] [k] xfs_next_bit 1.44% [kernel] [k] kmem_cache_free 1.41% [kernel] [k] _raw_spin_unlock_irqrestore 1.34% [xfs] [k] xfs_buf_offset 1.20% [kernel] [k] link_path_walk 1.16% [kernel] [k] kfree 1.11% [kernel] [k] memset 1.04% [xfs] [k] xfs_dir2_node_addname_int 0.94% [xfs] [k] xfs_da_do_buf 0.92% [xfs] [k] xfs_btree_lookup 0.89% [xfs] [k] xfs_buf_item_size
time: 1341306607 PerfTop: 1455 irqs/sec kernel:86.8% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
12.14% [unknown] [.] 0x00007f84a7766b99 5.36% [kernel] [k] page_fault 4.12% [kernel] [k] _raw_spin_lock 4.02% [kernel] [k] memcpy 2.54% [xfs] [k] _xfs_buf_find 2.41% [kernel] [k] kmem_cache_alloc 1.69% [kernel] [k] _raw_spin_lock_irqsave 1.56% [kernel] [k] __kmalloc 1.49% [xfs] [k] xfs_next_bit 1.47% [kernel] [k] __d_lookup 1.42% [kernel] [k] _raw_spin_unlock_irqrestore 1.39% [xfs] [k] xfs_buf_offset 1.39% cc1 [.] 0x0000000000210978 1.37% [kernel] [k] kmem_cache_free 1.24% [kernel] [k] link_path_walk 1.17% [kernel] [k] memset 1.16% [kernel] [k] kfree 1.07% [xfs] [k] xfs_dir2_node_addname_int 0.99% [xfs] [k] xfs_buf_item_size 0.92% [xfs] [k] xfs_da_do_buf 0.91% [xfs] [k] xfs_btree_lookup
time: 1341306613 PerfTop: 1245 irqs/sec kernel:87.3% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
12.05% [unknown] [.] 0x00007f84a7766b99 5.40% [kernel] [k] page_fault 4.10% [kernel] [k] _raw_spin_lock 4.06% [kernel] [k] memcpy 2.74% [xfs] [k] _xfs_buf_find 2.40% [kernel] [k] kmem_cache_alloc 1.64% [kernel] [k] _raw_spin_lock_irqsave 1.58% [xfs] [k] xfs_next_bit 1.54% [kernel] [k] __kmalloc 1.49% [kernel] [k] __d_lookup 1.45% [kernel] [k] _raw_spin_unlock_irqrestore 1.41% [kernel] [k] kmem_cache_free 1.35% [xfs] [k] xfs_buf_offset 1.25% [kernel] [k] link_path_walk 1.22% [kernel] [k] kfree 1.16% [kernel] [k] memset 1.15% cc1 [.] 0x0000000000210978 1.02% [xfs] [k] xfs_buf_item_size 1.00% [xfs] [k] xfs_dir2_node_addname_int 0.92% [xfs] [k] xfs_btree_lookup 0.91% [xfs] [k] xfs_da_do_buf
time: 1341306613 PerfTop: 1433 irqs/sec kernel:87.2% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
12.04% [unknown] [.] 0x00007f84a7766b99 5.30% [kernel] [k] page_fault 4.08% [kernel] [k] memcpy 4.07% [kernel] [k] _raw_spin_lock 2.88% [xfs] [k] _xfs_buf_find 2.50% [kernel] [k] kmem_cache_alloc 1.72% [kernel] [k] _raw_spin_lock_irqsave 1.68% [xfs] [k] xfs_next_bit 1.56% [kernel] [k] __d_lookup 1.54% [kernel] [k] __kmalloc 1.48% [kernel] [k] _raw_spin_unlock_irqrestore 1.46% [kernel] [k] kmem_cache_free 1.40% [xfs] [k] xfs_buf_offset 1.25% [kernel] [k] link_path_walk 1.21% [kernel] [k] memset 1.18% [kernel] [k] kfree 1.04% [xfs] [k] xfs_buf_item_size 1.02% [xfs] [k] xfs_dir2_node_addname_int 0.95% [xfs] [k] xfs_btree_lookup 0.94% cc1 [.] 0x0000000000210978 0.90% [xfs] [k] xfs_da_do_buf
time: 1341306613 PerfTop: 1118 irqs/sec kernel:87.2% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
no symbols found in /usr/bin/vmstat, maybe install a debug package? 12.03% [unknown] [.] 0x00007f84a7766b99 5.48% [kernel] [k] page_fault 4.21% [kernel] [k] memcpy 4.11% [kernel] [k] _raw_spin_lock 2.98% [xfs] [k] _xfs_buf_find 2.47% [kernel] [k] kmem_cache_alloc 1.81% [kernel] [k] _raw_spin_lock_irqsave 1.72% [xfs] [k] xfs_next_bit 1.51% [kernel] [k] __kmalloc 1.48% [kernel] [k] kmem_cache_free 1.48% [kernel] [k] __d_lookup 1.47% [kernel] [k] _raw_spin_unlock_irqrestore 1.39% [xfs] [k] xfs_buf_offset 1.23% [kernel] [k] link_path_walk 1.19% [kernel] [k] memset 1.19% [kernel] [k] kfree 1.07% [xfs] [k] xfs_dir2_node_addname_int 1.01% [xfs] [k] xfs_buf_item_size 0.98% [xfs] [k] xfs_btree_lookup 0.93% [xfs] [k] xfs_buf_item_format 0.91% [xfs] [k] xfs_da_do_buf
time: 1341306617 PerfTop: 1454 irqs/sec kernel:87.6% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.93% [unknown] [.] 0x00007f84a7766b99 5.42% [kernel] [k] page_fault 4.28% [kernel] [k] memcpy 4.20% [kernel] [k] _raw_spin_lock 3.15% [xfs] [k] _xfs_buf_find 2.52% [kernel] [k] kmem_cache_alloc 1.76% [kernel] [k] _raw_spin_lock_irqsave 1.72% [xfs] [k] xfs_next_bit 1.59% [kernel] [k] __d_lookup 1.51% [kernel] [k] __kmalloc 1.49% [kernel] [k] _raw_spin_unlock_irqrestore 1.48% [kernel] [k] kmem_cache_free 1.40% [xfs] [k] xfs_buf_offset 1.29% [kernel] [k] memset 1.20% [kernel] [k] link_path_walk 1.17% [kernel] [k] kfree 1.09% [xfs] [k] xfs_dir2_node_addname_int 1.01% [xfs] [k] xfs_buf_item_size 0.95% [xfs] [k] xfs_btree_lookup 0.94% [xfs] [k] xfs_da_do_buf 0.91% [xfs] [k] xfs_buf_item_format
time: 1341306617 PerfTop: 1758 irqs/sec kernel:90.2% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
10.99% [unknown] [.] 0x00007f84a7766b99 5.40% [kernel] [k] _raw_spin_lock 4.82% [kernel] [k] page_fault 4.04% [kernel] [k] memcpy 3.86% [xfs] [k] _xfs_buf_find 2.31% [kernel] [k] kmem_cache_alloc 2.03% [kernel] [k] _raw_spin_lock_irqsave 1.67% [kernel] [k] _raw_spin_unlock_irqrestore 1.60% [kernel] [k] __d_lookup 1.60% [xfs] [k] xfs_next_bit 1.44% [kernel] [k] __kmalloc 1.36% [xfs] [k] xfs_buf_offset 1.35% [kernel] [k] kmem_cache_free 1.17% [kernel] [k] kfree 1.16% [kernel] [k] memset 1.08% [kernel] [k] link_path_walk 0.98% [xfs] [k] xfs_dir2_node_addname_int 0.97% [xfs] [k] xfs_btree_lookup 0.92% [xfs] [k] xfs_perag_put 0.90% [xfs] [k] xfs_buf_item_size 0.84% [xfs] [k] xfs_da_do_buf
time: 1341306623 PerfTop: 1022 irqs/sec kernel:88.6% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
10.93% [unknown] [.] 0x00007f84a7766b99 5.34% [kernel] [k] _raw_spin_lock 4.82% [kernel] [k] page_fault 4.01% [kernel] [k] memcpy 4.01% [xfs] [k] _xfs_buf_find 2.28% [kernel] [k] kmem_cache_alloc 2.00% [kernel] [k] _raw_spin_lock_irqsave 1.68% [kernel] [k] _raw_spin_unlock_irqrestore 1.60% [xfs] [k] xfs_next_bit 1.59% [kernel] [k] __d_lookup 1.41% [kernel] [k] __kmalloc 1.39% [kernel] [k] kmem_cache_free 1.35% [xfs] [k] xfs_buf_offset 1.15% [kernel] [k] kfree 1.15% [kernel] [k] memset 1.09% [kernel] [k] link_path_walk 0.98% [xfs] [k] xfs_dir2_node_addname_int 0.98% [xfs] [k] xfs_btree_lookup 0.91% [xfs] [k] xfs_perag_put 0.88% [xfs] [k] xfs_buf_item_size 0.86% [xfs] [k] xfs_da_do_buf
time: 1341306623 PerfTop: 1430 irqs/sec kernel:87.6% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.05% [unknown] [.] 0x00007f84a7766b99 5.24% [kernel] [k] _raw_spin_lock 4.89% [kernel] [k] page_fault 4.13% [kernel] [k] memcpy 3.96% [xfs] [k] _xfs_buf_find 2.35% [kernel] [k] kmem_cache_alloc 1.95% [kernel] [k] _raw_spin_lock_irqsave 1.77% [kernel] [k] _raw_spin_unlock_irqrestore 1.63% [kernel] [k] __d_lookup 1.54% [xfs] [k] xfs_next_bit 1.42% [kernel] [k] __kmalloc 1.41% [kernel] [k] kmem_cache_free 1.32% [xfs] [k] xfs_buf_offset 1.16% [kernel] [k] memset 1.11% [kernel] [k] kfree 1.10% [kernel] [k] link_path_walk 1.05% [xfs] [k] xfs_dir2_node_addname_int 0.99% [xfs] [k] xfs_btree_lookup 0.91% [xfs] [k] xfs_buf_item_size 0.87% [xfs] [k] xfs_da_do_buf 0.87% [xfs] [k] xfs_perag_put
time: 1341306623 PerfTop: 1267 irqs/sec kernel:87.1% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.20% [unknown] [.] 0x00007f84a7766b99 5.08% [kernel] [k] _raw_spin_lock 4.85% [kernel] [k] page_fault 4.12% [kernel] [k] memcpy 3.96% [xfs] [k] _xfs_buf_find 2.41% [kernel] [k] kmem_cache_alloc 1.94% [kernel] [k] _raw_spin_lock_irqsave 1.77% [kernel] [k] _raw_spin_unlock_irqrestore 1.61% [kernel] [k] __d_lookup 1.50% [xfs] [k] xfs_next_bit 1.44% [kernel] [k] __kmalloc 1.40% [kernel] [k] kmem_cache_free 1.31% [xfs] [k] xfs_buf_offset no symbols found in /usr/bin/iostat, maybe install a debug package? 1.16% [kernel] [k] memset 1.11% [kernel] [k] kfree 1.06% [kernel] [k] link_path_walk 1.04% [xfs] [k] xfs_dir2_node_addname_int 1.01% [xfs] [k] xfs_btree_lookup 0.95% [xfs] [k] xfs_buf_item_size 0.90% [xfs] [k] xfs_da_do_buf 0.84% [xfs] [k] xfs_perag_put
time: 1341306629 PerfTop: 1399 irqs/sec kernel:88.3% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.12% [unknown] [.] 0x00007f84a7766b99 5.13% [kernel] [k] _raw_spin_lock 4.85% [kernel] [k] page_fault 4.23% [kernel] [k] memcpy 4.03% [xfs] [k] _xfs_buf_find 2.37% [kernel] [k] kmem_cache_alloc 1.96% [kernel] [k] _raw_spin_lock_irqsave 1.69% [kernel] [k] _raw_spin_unlock_irqrestore 1.63% [kernel] [k] __d_lookup 1.50% [xfs] [k] xfs_next_bit 1.45% [kernel] [k] __kmalloc 1.35% [kernel] [k] kmem_cache_free 1.32% [xfs] [k] xfs_buf_offset 1.17% [kernel] [k] memset 1.09% [kernel] [k] kfree 1.07% [xfs] [k] xfs_dir2_node_addname_int 1.07% [kernel] [k] link_path_walk 1.04% [xfs] [k] xfs_btree_lookup 1.02% [xfs] [k] xfs_buf_item_size 0.93% [xfs] [k] xfs_da_do_buf 0.84% [xfs] [k] xfs_buf_item_format
time: 1341306629 PerfTop: 1225 irqs/sec kernel:87.5% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.15% [unknown] [.] 0x00007f84a7766b99 5.02% [kernel] [k] _raw_spin_lock 4.85% [kernel] [k] page_fault 4.22% [kernel] [k] memcpy 4.19% [xfs] [k] _xfs_buf_find 2.32% [kernel] [k] kmem_cache_alloc 1.94% [kernel] [k] _raw_spin_lock_irqsave 1.71% [kernel] [k] __d_lookup 1.68% [kernel] [k] _raw_spin_unlock_irqrestore 1.54% [xfs] [k] xfs_next_bit 1.51% [kernel] [k] __kmalloc 1.36% [kernel] [k] kmem_cache_free 1.28% [xfs] [k] xfs_buf_offset 1.14% [kernel] [k] memset 1.09% [kernel] [k] kfree 1.06% [kernel] [k] link_path_walk 1.02% [xfs] [k] xfs_dir2_node_addname_int 0.99% [xfs] [k] xfs_buf_item_size 0.99% [xfs] [k] xfs_btree_lookup 0.92% [xfs] [k] xfs_da_do_buf 0.86% [kernel] [k] s_show
time: 1341306629 PerfTop: 1400 irqs/sec kernel:87.4% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.23% [unknown] [.] 0x00007f84a7766b99 5.07% [kernel] [k] _raw_spin_lock 4.87% [kernel] [k] page_fault 4.27% [xfs] [k] _xfs_buf_find 4.18% [kernel] [k] memcpy 2.31% [kernel] [k] kmem_cache_alloc 1.94% [kernel] [k] _raw_spin_lock_irqsave 1.73% [kernel] [k] __d_lookup 1.66% [kernel] [k] _raw_spin_unlock_irqrestore 1.49% [xfs] [k] xfs_next_bit 1.49% [kernel] [k] __kmalloc 1.40% [kernel] [k] kmem_cache_free 1.29% [xfs] [k] xfs_buf_offset 1.11% [kernel] [k] kfree 1.07% [kernel] [k] memset 1.07% [kernel] [k] link_path_walk 1.05% [xfs] [k] xfs_dir2_node_addname_int 0.99% [xfs] [k] xfs_buf_item_size 0.97% [xfs] [k] xfs_btree_lookup 0.93% [xfs] [k] xfs_da_do_buf 0.89% [kernel] [k] s_show
time: 1341306635 PerfTop: 1251 irqs/sec kernel:87.9% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.20% [unknown] [.] 0x00007f84a7766b99 5.10% [kernel] [k] _raw_spin_lock 4.82% [kernel] [k] page_fault 4.29% [xfs] [k] _xfs_buf_find 4.19% [kernel] [k] memcpy 2.26% [kernel] [k] kmem_cache_alloc 1.87% [kernel] [k] _raw_spin_lock_irqsave 1.83% [kernel] [k] __d_lookup 1.64% [kernel] [k] _raw_spin_unlock_irqrestore 1.53% [kernel] [k] __kmalloc 1.49% [xfs] [k] xfs_next_bit 1.41% [kernel] [k] kmem_cache_free 1.32% [xfs] [k] xfs_buf_offset 1.10% [kernel] [k] link_path_walk 1.09% [kernel] [k] memset 1.08% [kernel] [k] kfree 1.03% [xfs] [k] xfs_dir2_node_addname_int 0.99% [xfs] [k] xfs_buf_item_size 0.98% [xfs] [k] xfs_btree_lookup 0.96% [kernel] [k] s_show 0.93% [xfs] [k] xfs_da_do_buf
time: 1341306635 PerfTop: 1429 irqs/sec kernel:88.3% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.18% [unknown] [.] 0x00007f84a7766b99 5.13% [kernel] [k] _raw_spin_lock 4.82% [kernel] [k] page_fault 4.28% [xfs] [k] _xfs_buf_find 4.21% [kernel] [k] memcpy 2.23% [kernel] [k] kmem_cache_alloc 1.90% [kernel] [k] _raw_spin_lock_irqsave 1.83% [kernel] [k] __d_lookup 1.67% [kernel] [k] _raw_spin_unlock_irqrestore 1.52% [kernel] [k] __kmalloc 1.52% [xfs] [k] xfs_next_bit 1.36% [kernel] [k] kmem_cache_free 1.34% [xfs] [k] xfs_buf_offset 1.11% [kernel] [k] link_path_walk 1.11% [kernel] [k] memset 1.08% [kernel] [k] kfree 1.03% [xfs] [k] xfs_buf_item_size 1.03% [xfs] [k] xfs_dir2_node_addname_int 1.01% [kernel] [k] s_show 0.98% [xfs] [k] xfs_btree_lookup 0.94% [xfs] [k] xfs_da_do_buf
time: 1341306635 PerfTop: 1232 irqs/sec kernel:88.9% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.11% [unknown] [.] 0x00007f84a7766b99 5.13% [kernel] [k] _raw_spin_lock 4.87% [kernel] [k] page_fault 4.33% [xfs] [k] _xfs_buf_find 4.16% [kernel] [k] memcpy 2.24% [kernel] [k] kmem_cache_alloc 1.84% [kernel] [k] _raw_spin_lock_irqsave 1.82% [kernel] [k] __d_lookup 1.65% [kernel] [k] _raw_spin_unlock_irqrestore 1.50% [xfs] [k] xfs_next_bit 1.49% [kernel] [k] __kmalloc 1.34% [kernel] [k] kmem_cache_free 1.32% [xfs] [k] xfs_buf_offset 1.13% [kernel] [k] link_path_walk 1.13% [kernel] [k] kfree 1.11% [kernel] [k] memset 1.06% [kernel] [k] s_show 1.03% [xfs] [k] xfs_buf_item_size 1.02% [xfs] [k] xfs_dir2_node_addname_int 0.98% [xfs] [k] xfs_btree_lookup 0.94% [xfs] [k] xfs_da_do_buf
time: 1341306639 PerfTop: 1444 irqs/sec kernel:87.3% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
11.19% [unknown] [.] 0x00007f84a7766b99 5.10% [kernel] [k] _raw_spin_lock 4.95% [kernel] [k] page_fault 4.40% [xfs] [k] _xfs_buf_find 4.10% [kernel] [k] memcpy 2.20% [kernel] [k] kmem_cache_alloc 1.93% [kernel] [k] _raw_spin_lock_irqsave 1.81% [kernel] [k] __d_lookup 1.59% [kernel] [k] _raw_spin_unlock_irqrestore 1.50% [xfs] [k] xfs_next_bit 1.48% [kernel] [k] __kmalloc 1.37% [kernel] [k] kmem_cache_free 1.36% [xfs] [k] xfs_buf_offset 1.15% [kernel] [k] memset 1.12% [kernel] [k] s_show 1.12% [kernel] [k] link_path_walk 1.10% [kernel] [k] kfree 1.02% [xfs] [k] xfs_buf_item_size 0.99% [xfs] [k] xfs_btree_lookup 0.97% [xfs] [k] xfs_dir2_node_addname_int 0.94% [xfs] [k] xfs_da_do_buf
time: 1341306639 PerfTop: 1195 irqs/sec kernel:90.9% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
10.00% [unknown] [.] 0x00007f84a7766b99 5.17% [kernel] [k] _raw_spin_lock 4.44% [xfs] [k] _xfs_buf_find 4.37% [kernel] [k] page_fault 4.37% [kernel] [k] memcpy 2.30% [kernel] [k] kmem_cache_alloc 1.90% [kernel] [k] _raw_spin_lock_irqsave 1.63% [kernel] [k] __d_lookup 1.62% [kernel] [k] _raw_spin_unlock_irqrestore 1.59% [xfs] [k] xfs_buf_offset 1.50% [kernel] [k] kmem_cache_free 1.50% [kernel] [k] __kmalloc 1.49% [xfs] [k] xfs_next_bit 1.33% [kernel] [k] memset 1.28% [kernel] [k] kfree 1.11% [xfs] [k] xfs_buf_item_size 1.07% [kernel] [k] s_show 1.07% [kernel] [k] link_path_walk 0.93% [xfs] [k] xfs_btree_lookup 0.90% [xfs] [k] xfs_da_do_buf 0.84% [xfs] [k] xfs_dir2_node_addname_int
time: 1341306645 PerfTop: 1097 irqs/sec kernel:95.8% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
7.51% [unknown] [.] 0x00007f84a7766b99 5.02% [kernel] [k] _raw_spin_lock 4.63% [kernel] [k] memcpy 4.51% [xfs] [k] _xfs_buf_find 3.32% [kernel] [k] page_fault 2.37% [kernel] [k] kmem_cache_alloc 1.87% [kernel] [k] _raw_spin_lock_irqsave 1.77% [xfs] [k] xfs_buf_offset 1.75% [kernel] [k] __kmalloc 1.73% [xfs] [k] xfs_next_bit 1.65% [kernel] [k] memset 1.60% [kernel] [k] _raw_spin_unlock_irqrestore 1.53% [kernel] [k] kfree 1.52% [kernel] [k] kmem_cache_free 1.44% [xfs] [k] xfs_trans_ail_cursor_first 1.26% [kernel] [k] __d_lookup 1.26% [xfs] [k] xfs_buf_item_size 1.05% [kernel] [k] s_show 1.03% [xfs] [k] xfs_buf_item_format 0.92% [kernel] [k] __d_lookup_rcu 0.87% [kernel] [k] link_path_walk
time: 1341306645 PerfTop: 1038 irqs/sec kernel:95.2% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
5.89% [unknown] [.] 0x00007f84a7766b99 5.18% [kernel] [k] memcpy 4.60% [xfs] [k] _xfs_buf_find 4.52% [kernel] [k] _raw_spin_lock 2.60% [kernel] [k] page_fault 2.42% [kernel] [k] kmem_cache_alloc 1.99% [kernel] [k] __kmalloc 1.96% [xfs] [k] xfs_next_bit 1.93% [xfs] [k] xfs_buf_offset 1.84% [kernel] [k] _raw_spin_lock_irqsave 1.83% [kernel] [k] memset 1.80% [kernel] [k] kmem_cache_free 1.68% [kernel] [k] kfree 1.47% [xfs] [k] xfs_buf_item_size 1.45% [kernel] [k] _raw_spin_unlock_irqrestore 1.18% [kernel] [k] __d_lookup_rcu 1.13% [xfs] [k] xfs_trans_ail_cursor_first 1.12% [xfs] [k] xfs_buf_item_format 1.04% [kernel] [k] s_show 1.01% [kernel] [k] __d_lookup 0.93% [xfs] [k] xfs_da_do_buf
time: 1341306645 PerfTop: 1087 irqs/sec kernel:96.0% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
5.27% [kernel] [k] memcpy 4.77% [unknown] [.] 0x00007f84a7766b99 4.69% [xfs] [k] _xfs_buf_find 4.56% [kernel] [k] _raw_spin_lock 2.47% [kernel] [k] kmem_cache_alloc 2.18% [xfs] [k] xfs_next_bit 2.11% [kernel] [k] page_fault 2.00% [xfs] [k] xfs_buf_offset 1.99% [kernel] [k] __kmalloc 1.96% [kernel] [k] kmem_cache_free 1.85% [kernel] [k] kfree 1.82% [kernel] [k] memset 1.75% [kernel] [k] _raw_spin_lock_irqsave 1.58% [xfs] [k] xfs_buf_item_size 1.41% [kernel] [k] _raw_spin_unlock_irqrestore 1.23% [kernel] [k] __d_lookup_rcu 1.21% [xfs] [k] xfs_buf_item_format 0.99% [kernel] [k] s_show 0.97% [xfs] [k] xfs_perag_put 0.92% [xfs] [k] xfs_da_do_buf 0.92% [xfs] [k] xfs_trans_ail_cursor_first
time: 1341306651 PerfTop: 1157 irqs/sec kernel:96.5% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
5.53% [kernel] [k] memcpy 4.61% [xfs] [k] _xfs_buf_find 4.40% [kernel] [k] _raw_spin_lock 3.83% [unknown] [.] 0x00007f84a7766b99 2.67% [kernel] [k] kmem_cache_alloc 2.32% [xfs] [k] xfs_next_bit 2.21% [kernel] [k] __kmalloc 2.21% [xfs] [k] xfs_buf_offset 2.19% [kernel] [k] kmem_cache_free 1.92% [kernel] [k] memset 1.89% [kernel] [k] kfree 1.80% [xfs] [k] xfs_buf_item_size 1.70% [kernel] [k] page_fault 1.62% [kernel] [k] _raw_spin_lock_irqsave 1.50% [kernel] [k] _raw_spin_unlock_irqrestore 1.30% [xfs] [k] xfs_buf_item_format 1.27% [kernel] [k] __d_lookup_rcu 0.97% [xfs] [k] xfs_da_do_buf 0.96% [xfs] [k] xlog_cil_prepare_log_vecs 0.93% [kernel] [k] s_show 0.93% [xfs] [k] xfs_perag_put
time: 1341306651 PerfTop: 1073 irqs/sec kernel:95.5% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
5.76% [kernel] [k] memcpy 4.54% [xfs] [k] _xfs_buf_find 4.32% [kernel] [k] _raw_spin_lock 3.15% [unknown] [.] 0x00007f84a7766b99 2.77% [kernel] [k] kmem_cache_alloc 2.49% [xfs] [k] xfs_next_bit 2.36% [kernel] [k] __kmalloc 2.27% [kernel] [k] kmem_cache_free 2.20% [xfs] [k] xfs_buf_offset 1.88% [kernel] [k] memset 1.88% [kernel] [k] kfree 1.77% [xfs] [k] xfs_buf_item_size 1.62% [kernel] [k] _raw_spin_lock_irqsave 1.48% [kernel] [k] _raw_spin_unlock_irqrestore 1.42% [xfs] [k] xfs_buf_item_format 1.40% [kernel] [k] page_fault 1.39% [kernel] [k] __d_lookup_rcu 0.99% [xfs] [k] xfs_da_do_buf 0.96% [xfs] [k] xlog_cil_prepare_log_vecs 0.88% [kernel] [k] s_show 0.87% [xfs] [k] xfs_perag_put
time: 1341306651 PerfTop: 492 irqs/sec kernel:85.6% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
5.74% [kernel] [k] memcpy 4.48% [xfs] [k] _xfs_buf_find 4.27% [kernel] [k] _raw_spin_lock 3.00% [unknown] [.] 0x00007f84a7766b99 2.76% [kernel] [k] kmem_cache_alloc 2.54% [xfs] [k] xfs_next_bit 2.39% [kernel] [k] __kmalloc 2.30% [kernel] [k] kmem_cache_free 2.20% [xfs] [k] xfs_buf_offset no symbols found in /bin/ps, maybe install a debug package? 1.96% [kernel] [k] kfree 1.92% [kernel] [k] memset 1.75% [xfs] [k] xfs_buf_item_size 1.56% [kernel] [k] _raw_spin_lock_irqsave 1.48% [kernel] [k] _raw_spin_unlock_irqrestore 1.44% [xfs] [k] xfs_buf_item_format 1.39% [kernel] [k] __d_lookup_rcu 1.36% [kernel] [k] page_fault 0.99% [xfs] [k] xlog_cil_prepare_log_vecs 0.96% [xfs] [k] xfs_da_do_buf 0.86% [kernel] [k] s_show 0.85% [xfs] [k] xfs_perag_put
time: 1341306657 PerfTop: 70 irqs/sec kernel:72.9% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
5.73% [kernel] [k] memcpy 4.47% [xfs] [k] _xfs_buf_find 4.27% [kernel] [k] _raw_spin_lock 2.99% [unknown] [.] 0x00007f84a7766b99 2.75% [kernel] [k] kmem_cache_alloc 2.53% [xfs] [k] xfs_next_bit 2.39% [kernel] [k] __kmalloc 2.30% [kernel] [k] kmem_cache_free 2.20% [xfs] [k] xfs_buf_offset 1.96% [kernel] [k] kfree 1.92% [kernel] [k] memset 1.75% [xfs] [k] xfs_buf_item_size 1.56% [kernel] [k] _raw_spin_lock_irqsave 1.49% [kernel] [k] _raw_spin_unlock_irqrestore 1.43% [xfs] [k] xfs_buf_item_format 1.38% [kernel] [k] __d_lookup_rcu 1.37% [kernel] [k] page_fault 0.98% [xfs] [k] xlog_cil_prepare_log_vecs 0.96% [xfs] [k] xfs_da_do_buf 0.89% [kernel] [k] s_show 0.85% [xfs] [k] xfs_perag_put
time: 1341306657 PerfTop: 87 irqs/sec kernel:71.3% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
5.72% [kernel] [k] memcpy 4.45% [xfs] [k] _xfs_buf_find 4.25% [kernel] [k] _raw_spin_lock 2.99% [unknown] [.] 0x00007f84a7766b99 2.74% [kernel] [k] kmem_cache_alloc 2.52% [xfs] [k] xfs_next_bit 2.38% [kernel] [k] __kmalloc 2.29% [kernel] [k] kmem_cache_free 2.19% [xfs] [k] xfs_buf_offset 1.95% [kernel] [k] kfree 1.91% [kernel] [k] memset 1.74% [xfs] [k] xfs_buf_item_size 1.56% [kernel] [k] _raw_spin_lock_irqsave 1.48% [kernel] [k] _raw_spin_unlock_irqrestore 1.43% [xfs] [k] xfs_buf_item_format 1.38% [kernel] [k] page_fault 1.38% [kernel] [k] __d_lookup_rcu 0.98% [xfs] [k] xlog_cil_prepare_log_vecs 0.96% [xfs] [k] xfs_da_do_buf 0.93% [kernel] [k] s_show 0.84% [xfs] [k] xfs_perag_put
time: 1341306657 PerfTop: 88 irqs/sec kernel:68.2% exact: 0.0% [1000Hz cycles], (all, 8 CPUs) -------------------------------------------------------------------------------
5.69% [kernel] [k] memcpy 4.42% [xfs] [k] _xfs_buf_find 4.25% [kernel] [k] _raw_spin_lock 2.98% [unknown] [.] 0x00007f84a7766b99
On Tue, Jul 03, 2012 at 11:59:51AM +0100, Mel Gorman wrote:
Can you run latencytop to see if there is excessive starvation/wait times for allocation completion?
I'm not sure what format you are looking for. latencytop is shit for capturing information throughout a test and it does not easily allow you to record a snapshot of a test. You can record all the console output of course but that's a complete mess. I tried capturing /proc/latency_stats over time instead because that can be trivially sorted on a system-wide basis but as I write this I find that latency_stats was bust. It was just spitting out
Latency Top version : v0.1
and nothing else. Either latency_stats is broken or my config is. Not sure which it is right now and won't get enough time on this today to pinpoint it.
PEBKAC. Script that monitored /proc/latency_stats was not enabling latency top via /proc/sys/kernel/latencytop
On Tue, Jul 03, 2012 at 11:59:51AM +0100, Mel Gorman wrote:
On Tue, Jul 03, 2012 at 10:19:28AM +1000, Dave Chinner wrote:
On Mon, Jul 02, 2012 at 08:35:16PM +0100, Mel Gorman wrote:
Adding dri-devel and a few others because an i915 patch contributed to the regression.
On Mon, Jul 02, 2012 at 03:32:15PM +0100, Mel Gorman wrote:
On Mon, Jul 02, 2012 at 02:32:26AM -0400, Christoph Hellwig wrote:
It increases the CPU overhead (dirty_inode can be called up to 4 times per write(2) call, IIRC), so with limited numbers of threads/limited CPU power it will result in lower performance. Where you have lots of CPU power, there will be little difference in performance...
When I checked it it could only be called twice, and we'd already optimize away the second call. I'd defintively like to track down where the performance changes happend, at least to a major version but even better to a -rc or git commit.
By all means feel free to run the test yourself and run the bisection :)
It's rare but on this occasion the test machine is idle so I started an automated git bisection. As you know the milage with an automated bisect varies so it may or may not find the right commit. Test machine is sandy so http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-metadata-... is the report of interest. The script is doing a full search between v3.3 and v3.4 for a point where average files/sec for fsmark-single drops below 25000. I did not limit the search to fs/xfs on the off-chance that it is an apparently unrelated patch that caused the problem.
It was obvious very quickly that there were two distinct regression so I ran two bisections. One led to a XFS and the other led to an i915 patch that enables RC6 to reduce power usage.
[aa464191: drm/i915: enable plain RC6 on Sandy Bridge by default]
Doesn't seem to be the major cause of the regression. By itself, it has impact, but the majority comes from the XFS change...
The fact it has an impact at all is weird but lets see what the DRI folks think about it.
Well, presuming I understand things correctly the cpu die only goes into the lowest sleep state (which iirc switches off l3 caches and interconnects) when both the cpu and gpu are in the lowest sleep state. rc6 is that deep-sleep state for the gpu, so without that enabled your system won't go into these deep-sleep states.
I guess the slight changes in wakeup latency, power consumption (cuts about 10W on an idle desktop snb with resulting big effect on what turbo boost can sustain for short amounts of time) and all the follow-on effects are good enough to massively change timing-critical things.
So this having an effect isn't too weird.
Obviously, if you also have X running while doing these tests there's the chance that the gpu dies because of an issue when waking up from rc6 (we've known a few of these), but if no drm client is up, that shouldn't be possible. So please retest without X running if that hasn't been done already.
Yours, Daniel
On Tue, Jul 03, 2012 at 02:31:19PM +0200, Daniel Vetter wrote:
On Tue, Jul 03, 2012 at 11:59:51AM +0100, Mel Gorman wrote:
On Tue, Jul 03, 2012 at 10:19:28AM +1000, Dave Chinner wrote:
On Mon, Jul 02, 2012 at 08:35:16PM +0100, Mel Gorman wrote:
Adding dri-devel and a few others because an i915 patch contributed to the regression.
On Mon, Jul 02, 2012 at 03:32:15PM +0100, Mel Gorman wrote:
On Mon, Jul 02, 2012 at 02:32:26AM -0400, Christoph Hellwig wrote:
> It increases the CPU overhead (dirty_inode can be called up to 4 > times per write(2) call, IIRC), so with limited numbers of > threads/limited CPU power it will result in lower performance. Where > you have lots of CPU power, there will be little difference in > performance...
When I checked it it could only be called twice, and we'd already optimize away the second call. I'd defintively like to track down where the performance changes happend, at least to a major version but even better to a -rc or git commit.
By all means feel free to run the test yourself and run the bisection :)
It's rare but on this occasion the test machine is idle so I started an automated git bisection. As you know the milage with an automated bisect varies so it may or may not find the right commit. Test machine is sandy so http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-metadata-... is the report of interest. The script is doing a full search between v3.3 and v3.4 for a point where average files/sec for fsmark-single drops below 25000. I did not limit the search to fs/xfs on the off-chance that it is an apparently unrelated patch that caused the problem.
It was obvious very quickly that there were two distinct regression so I ran two bisections. One led to a XFS and the other led to an i915 patch that enables RC6 to reduce power usage.
[aa464191: drm/i915: enable plain RC6 on Sandy Bridge by default]
Doesn't seem to be the major cause of the regression. By itself, it has impact, but the majority comes from the XFS change...
The fact it has an impact at all is weird but lets see what the DRI folks think about it.
Well, presuming I understand things correctly the cpu die only goes into the lowest sleep state (which iirc switches off l3 caches and interconnects) when both the cpu and gpu are in the lowest sleep state.
I made a mistake in my previous mail. gdm and X were were *not* running. Once the screen blanked I would guess the GPU is in a low sleep state the majority of the time.
rc6 is that deep-sleep state for the gpu, so without that enabled your system won't go into these deep-sleep states.
I guess the slight changes in wakeup latency, power consumption (cuts about 10W on an idle desktop snb with resulting big effect on what turbo boost can sustain for short amounts of time) and all the follow-on effects are good enough to massively change timing-critical things.
Maybe. How aggressively is the lowest sleep state entered and how long does it take to exit?
So this having an effect isn't too weird.
Obviously, if you also have X running while doing these tests there's the chance that the gpu dies because of an issue when waking up from rc6 (we've known a few of these), but if no drm client is up, that shouldn't be possible. So please retest without X running if that hasn't been done already.
Again, sorry for the confusion but the posted results are without X running.
On Tue, Jul 3, 2012 at 9:31 AM, Daniel Vetter daniel@ffwll.ch wrote:
Well, presuming I understand things correctly the cpu die only goes into the lowest sleep state (which iirc switches off l3 caches and interconnects) when both the cpu and gpu are in the lowest sleep state. rc6 is that deep-sleep state for the gpu, so without that enabled your system won't go into these deep-sleep states.
I guess the slight changes in wakeup latency, power consumption (cuts about 10W on an idle desktop snb with resulting big effect on what turbo boost can sustain for short amounts of time) and all the follow-on effects are good enough to massively change timing-critical things.
The sad side effect is that the software has very little control over the RC6 entry and exit, the hardware enters and leaves RC6 state on its own when it detects that the GPU is idle beyond a threshold. Chances are that if you are not running any GPU workload, the GPU simple enters RC6 state and stays there.
It is possible to observe the current state and also time spent in rc6 by looking at the /sys/kernel/debug/dri/0/i915_drpc_info file.
One other effect of RC6 is that it also allows CPU to go into higher turbo modes as it has more watts to spend while GPU is idle, perhaps this is what causes the issue here?
On Tue, Jul 03, 2012 at 11:59:51AM +0100, Mel Gorman wrote:
On Tue, Jul 03, 2012 at 10:19:28AM +1000, Dave Chinner wrote:
On Mon, Jul 02, 2012 at 08:35:16PM +0100, Mel Gorman wrote:
Adding dri-devel and a few others because an i915 patch contributed to the regression.
On Mon, Jul 02, 2012 at 03:32:15PM +0100, Mel Gorman wrote:
On Mon, Jul 02, 2012 at 02:32:26AM -0400, Christoph Hellwig wrote:
It increases the CPU overhead (dirty_inode can be called up to 4 times per write(2) call, IIRC), so with limited numbers of threads/limited CPU power it will result in lower performance. Where you have lots of CPU power, there will be little difference in performance...
When I checked it it could only be called twice, and we'd already optimize away the second call. I'd defintively like to track down where the performance changes happend, at least to a major version but even better to a -rc or git commit.
By all means feel free to run the test yourself and run the bisection :)
It's rare but on this occasion the test machine is idle so I started an automated git bisection. As you know the milage with an automated bisect varies so it may or may not find the right commit. Test machine is sandy so http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-metadata-... is the report of interest. The script is doing a full search between v3.3 and v3.4 for a point where average files/sec for fsmark-single drops below 25000. I did not limit the search to fs/xfs on the off-chance that it is an apparently unrelated patch that caused the problem.
It was obvious very quickly that there were two distinct regression so I ran two bisections. One led to a XFS and the other led to an i915 patch that enables RC6 to reduce power usage.
[aa464191: drm/i915: enable plain RC6 on Sandy Bridge by default]
Doesn't seem to be the major cause of the regression. By itself, it has impact, but the majority comes from the XFS change...
The fact it has an impact at all is weird but lets see what the DRI folks think about it.
[c999a223: xfs: introduce an allocation workqueue]
Which indicates that there is workqueue scheduling issues, I think. The same amount of work is being done, but half of it is being pushed off into a workqueue to avoid stack overflow issues (*). I tested the above patch in anger on an 8p machine, similar to the machine you saw no regressions on, but the workload didn't drive it to being completely CPU bound (only about 90%) so the allocation work was probably always scheduled quickly.
What test were you using?
fsmark, dbench, compilebench, and a few fio workloads. Also, xfstests times each test and I keep track of overall runtime, and none of those showed any performance differential, either...
Indeed, running on a current 3.5-rc5 tree, my usual fsmark benchmarks are running at the same numbers I've been seeing since about 3.0 - somewhere around 18k files/s for a single thread, and 110-115k files/s for 8 threads.
I just ran your variant, and I'm getting about 20kfile/s for a single thread, which is about right because you're using smaller directories than I am (22500 files per dir vs 100k in my tests).
How many worker threads have been spawned on these machines that are showing the regression?
20 or 21 generally. An example list as spotted by top looks like
Pretty normal.
What is the context switch rate on the machines whenteh test is running?
.....
Vanilla average context switch rate 4278.53 Revert average context switch rate 1095
That seems about right, too.
Can you run latencytop to see if there is excessive starvation/wait times for allocation completion?
I'm not sure what format you are looking for.
Where the context switches are coming from, and how long they are abeing stalled for. Just to get the context switch locations, you can use perf on the sched:sched_switch event, but that doesn't give you stall times. Local testing tells me that about 40% of the switches are from xfs_alloc_vextent, 55% are from the work threads, and the rest are CPU idling events, which is exactly as I'd expect.
A pert top profile comparison might be informative, too...
I'm not sure if this is what you really wanted. I thought an oprofile or perf report would have made more sense but I recorded perf top over time anyway and it's at the end of the mail.
perf report and oprofile give you CPU usage across the run, it's not instantaneous and that's where all the interesting information is. e.g. a 5% sample in a 20s profile might be 5% per second for 20s, or it might be 100% for 1s - that's the behaviour run profiles cannot give you insight into....
As it is, the output you posted is nothing unusual.
For just these XFS tests I've uploaded a tarball of the logs to http://www.csn.ul.ie/~mel/postings/xfsbisect-20120703/xfsbisect-logs.tar.gz
Ok, so the main thing I missed when first looking at this is that you are concerned about single thread regressions. Well, I can't reproduce your results here. Single threaded with or without the workqueue based allocation gives me roughly 20k +/-0.5k files/s one a single disk, a 12 disk RAID0 array and a RAM disk on a 8p/4GB RAM machine. That's the same results I've been seeing since I wrote this patch almost 12 months ago....
So, given that this is a metadata intensive workload, the only extent allocation is going to be through inode and directory block allocation. These paths do not consume a large amount of stack, so we can tell the allocator not to switch to workqueue stack for these allocations easily.
The patch below does this. It completely removes all the allocation based context switches from the no-data fsmark workloads being used for this testing. It makes no noticable difference to performance here, so I'm interested if it solves the regression you are seeing on your machines.
Cheers,
Dave.
On Wed, Jul 04, 2012 at 10:47:06AM +1000, Dave Chinner wrote:
<SNIP> [c999a223: xfs: introduce an allocation workqueue]
Which indicates that there is workqueue scheduling issues, I think. The same amount of work is being done, but half of it is being pushed off into a workqueue to avoid stack overflow issues (*). I tested the above patch in anger on an 8p machine, similar to the machine you saw no regressions on, but the workload didn't drive it to being completely CPU bound (only about 90%) so the allocation work was probably always scheduled quickly.
What test were you using?
fsmark, dbench, compilebench, and a few fio workloads. Also, xfstests times each test and I keep track of overall runtime, and none of those showed any performance differential, either...
Sound. I have some coverage on some of the same tests. When I get to them I'll keep an eye on the 3.4 figures. It might be due to the disk I'm using. It's a single disk and nothing to write home about in terms of performance. It's not exactly XFS's usual target audience.
Indeed, running on a current 3.5-rc5 tree, my usual fsmark benchmarks are running at the same numbers I've been seeing since about 3.0 - somewhere around 18k files/s for a single thread, and 110-115k files/s for 8 threads.
I just ran your variant, and I'm getting about 20kfile/s for a single thread, which is about right because you're using smaller directories than I am (22500 files per dir vs 100k in my tests).
I had data for an fsmark-single test running with 30M files and FWIW the 3.4 performance figures were in line with 3.0 and later kernels.
How many worker threads have been spawned on these machines that are showing the regression?
20 or 21 generally. An example list as spotted by top looks like
Pretty normal.
What is the context switch rate on the machines whenteh test is running?
.....
Vanilla average context switch rate 4278.53 Revert average context switch rate 1095
That seems about right, too.
Can you run latencytop to see if there is excessive starvation/wait times for allocation completion?
I'm not sure what format you are looking for.
Where the context switches are coming from, and how long they are abeing stalled for.
Noted. Capturing latency_stats over time is enough to do that. It won't give a per-process breakdown but in the majority of cases that is not a problem. Extracting the data is a bit annoying but not impossible and better than parsing latencytop. Ideally, latencytop would be able to log data in some sensible format. hmmm.
Just to get the context switch locations, you can use perf on the sched:sched_switch event, but that doesn't give you stall times.
No, but both can be captured and roughly correlated with each other given sufficient motivation.
Local testing tells me that about 40% of the switches are from xfs_alloc_vextent, 55% are from the work threads, and the rest are CPU idling events, which is exactly as I'd expect.
A pert top profile comparison might be informative, too...
I'm not sure if this is what you really wanted. I thought an oprofile or perf report would have made more sense but I recorded perf top over time anyway and it's at the end of the mail.
perf report and oprofile give you CPU usage across the run, it's not instantaneous and that's where all the interesting information is. e.g. a 5% sample in a 20s profile might be 5% per second for 20s, or it might be 100% for 1s - that's the behaviour run profiles cannot give you insight into....
Fair point. I'll fix up the timestamping and keep the monitor for future reference.
As it is, the output you posted is nothing unusual.
Grand. I had taken a look but I saw nothing particularly unusual but I also was not 100% sure what I should be looking for.,
For just these XFS tests I've uploaded a tarball of the logs to http://www.csn.ul.ie/~mel/postings/xfsbisect-20120703/xfsbisect-logs.tar.gz
Ok, so the main thing I missed when first looking at this is that you are concerned about single thread regressions.
In this specific test, yes. In the original data I posted I had threaded benchmarks but they did not show the regression. This was a rerun with just the single threaded case. Generally I run both because I see bug reports involving both types of test.
Well, I can't reproduce your results here. Single threaded with or without the workqueue based allocation gives me roughly 20k +/-0.5k files/s one a single disk, a 12 disk RAID0 array and a RAM disk on a 8p/4GB RAM machine. That's the same results I've been seeing since I wrote this patch almost 12 months ago....
So, given that this is a metadata intensive workload, the only extent allocation is going to be through inode and directory block allocation. These paths do not consume a large amount of stack, so we can tell the allocator not to switch to workqueue stack for these allocations easily.
The patch below does this. It completely removes all the allocation based context switches from the no-data fsmark workloads being used for this testing. It makes no noticable difference to performance here, so I'm interested if it solves the regression you are seeing on your machines.
It does. nodefer-metadata is just your patch applied on top of 3.4 and is the right-most column. It's within the noise for the reverted patches and approximately the same performance as 3.3. If you look at the timing stats at the bottom you'll see that hte patch brings the System time way down so consider this a
Tested-by: Mel Gorman mgorman@suse.de
FS-Mark Single Threaded fsmark-single single-3.4.0 single-3.4.0 single-3.4.0 single-3.4.0 3.4.0-vanilla revert-aa464191 revert-c999a223 revert-both nodefer-metadata Files/s min 14176.40 ( 0.00%) 17830.60 (25.78%) 24186.70 (70.61%) 25108.00 (77.11%) 25448.40 (79.51%) Files/s mean 16783.35 ( 0.00%) 25029.69 (49.13%) 37513.72 (123.52%) 38169.97 (127.43%) 36393.09 (116.84%) Files/s stddev 1007.26 ( 0.00%) 2644.87 (162.58%) 5344.99 (430.65%) 5599.65 (455.93%) 5961.48 (491.85%) Files/s max 18475.40 ( 0.00%) 27966.10 (51.37%) 45564.60 (146.62%) 47918.10 (159.36%) 47146.20 (155.18%) Overhead min 593978.00 ( 0.00%) 386173.00 (34.99%) 253812.00 (57.27%) 247396.00 (58.35%) 248906.00 (58.10%) Overhead mean 637782.80 ( 0.00%) 429229.33 (32.70%) 322868.20 (49.38%) 287141.73 (54.98%) 284274.93 (55.43%) Overhead stddev 72440.72 ( 0.00%) 100056.96 (-38.12%) 175001.08 (-141.58%) 102018.14 (-40.83%) 114055.47 (-57.45%) Overhead max 855637.00 ( 0.00%) 753541.00 (11.93%) 880531.00 (-2.91%) 637932.00 (25.44%) 710720.00 (16.94%)
MMTests Statistics: duration Sys Time Running Test (seconds) 44.06 32.25 24.19 23.99 24.38 User+Sys Time Running Test (seconds) 50.19 36.35 27.24 26.7 27.12 Total Elapsed Time (seconds) 59.21 44.76 34.95 34.14 36.11
Thanks.
On Mon, Jul 02, 2012 at 08:35:16PM +0100, Mel Gorman wrote:
<SNIP>
It was obvious very quickly that there were two distinct regression so I ran two bisections. One led to a XFS and the other led to an i915 patch that enables RC6 to reduce power usage.
[c999a223: xfs: introduce an allocation workqueue] [aa464191: drm/i915: enable plain RC6 on Sandy Bridge by default]
gdm was running on the machine so i915 would have been in use.
Bah, more PEBKAC. gdm was *not* running on this machine. i915 is loaded but X is not.
On Tue, Jul 03, 2012 at 02:04:14PM +0100, Mel Gorman wrote:
On Mon, Jul 02, 2012 at 08:35:16PM +0100, Mel Gorman wrote:
<SNIP>
It was obvious very quickly that there were two distinct regression so I ran two bisections. One led to a XFS and the other led to an i915 patch that enables RC6 to reduce power usage.
[c999a223: xfs: introduce an allocation workqueue] [aa464191: drm/i915: enable plain RC6 on Sandy Bridge by default]
gdm was running on the machine so i915 would have been in use.
Bah, more PEBKAC. gdm was *not* running on this machine. i915 is loaded but X is not.
See my little explanation of rc6, just loading the driver will have effects. But I'm happy to know that the issue also happens without using it, makes it really unlikely it's an issue with the gpu or i915.ko ;-) -Daniel
dri-devel@lists.freedesktop.org
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