On 13.05.2014 22:27, Marek Olšák wrote:
I applied these two patches Christian sent to dri-devel:
drm/radeon: fix page directory update size estimation drm/radeon: fix buffer placement under memory pressure v2
on top of torvalds's master branch.
With latest kernel master (a991639c) I still see a regression, compared to 3.13 or 3.14, which have similar performance. Xonotic is about 7% slower. OpenArena and Unigine Tropics are also noticeably slower, but I didn't record accurate numbers.
Maybe the improved memory management has some overhead, but this is not acceptable IMHO. I'll try to investigate further.
Best regards Grigori
Marek
On Tue, May 13, 2014 at 10:19 PM, Grigori Goronzy greg@chown.ath.cx wrote:
On 13.05.2014 21:50, Marek Olšák wrote:
Hi Christian,
The performance regression I saw with piglit seems to be fixed with latest kernel git. It's difficult to bisect the kernel, because there are only merges between 3.14 and 3.15 and the merged committs are actually based on 3.14-rc1 and 3.14-rc4.
All seems to be fine with your fixes.
Which fixes have you applied? There are quite a few pending patches on dri-devel, that aren't yet part of drm-fixes-3.15.
Grigori
Marek
On Tue, May 13, 2014 at 5:31 PM, Christian König deathsimple@vodafone.de wrote:
Is the performance regression regression caused by the page table changes or something else?
I did made some tests with xonotic while developing it and it didn't showed anything obvious, but I didn't made tests on different systems.
Christian.
Am 13.05.2014 17:19, schrieb Marek Olšák:
Your latest patches fix the regression.
The performance regression can also be reproduced with piglit "-t texelFetch.fs".
Kernel 3.14: real 0m17.724s user 0m41.905s sys 0m11.299s
The problematic commit checked out + your fixes (without the PTE patch I think): real 0m23.474s user 1m1.008s sys 0m13.812s
Marek
On Tue, May 13, 2014 at 3:57 PM, Christian König deathsimple@vodafone.de wrote:
Am 13.05.2014 15:22, schrieb Alex Deucher:
> On Mon, May 12, 2014 at 7:38 PM, Grigori Goronzy greg@chown.ath.cx > wrote: >> >> >> I can confirm this fixes it for me, too. >> >> 3.15 with these fixes and the large PTE patches actually ends up >> being >> noticeably slower than earlier kernels with Xonotic, though. I wonder >> what's >> going on. > > > Allocation overhead?
Unlikely, Xonotic just allocates a single page table at start, which then gets extended to a certain rate until they no longer need more address space and are done with it.
Grigori, can you bisect and/or try to figure out what's wrong here?
Christian.
> >> Grigori >> >> >> On 12.05.2014 14:50, Christian König wrote: >>> >>> >>> I could reproduce the problem with xonotic and I think I've found >>> the >>> issue. >>> >>> Please test the attached patch. >>> >>> Thanks, >>> Christian. >>> >>> Am 11.05.2014 11:06, schrieb Christian König: >>>>> >>>>> >>>>> I have tested it and it doesn't fix the hangs. >>>> >>>> >>>> Yeah, thought so. Well it was just a guess. >>>> >>>>> (Also, I don't like the patch, because it reverts the behavior I >>>>> added >>>>> for userspace buffers.) >>>> >>>> >>>> Actually it shouldn't affect that. The alternative domain always >>>> contains GART even when userspace only specified VRAM as placement >>>> (as >>>> long as it is technical possible to do so). >>>> >>>> So what should happen is that TTM sees the current placement, >>>> matches >>>> that with the desired placement and should find that it doesn't >>>> need >>>> to move the buffer (we should just test if this behavior really >>>> works >>>> as expected). >>>> >>>> Christian. >>>> >>>> Am 10.05.2014 23:38, schrieb Marek Olšák: >>>>> >>>>> >>>>> Hi Christian, >>>>> >>>>> I have tested it and it doesn't fix the hangs. >>>>> >>>>> (Also, I don't like the patch, because it reverts the behavior I >>>>> added >>>>> for userspace buffers.) >>>>> >>>>> Marek >>>>> >>>>> >>>>> >>>>> On Sat, May 10, 2014 at 6:34 PM, Christian König >>>>> deathsimple@vodafone.de wrote: >>>>>> >>>>>> >>>>>> Couldn't reproduce the issue so far. So the attached patch is >>>>>> just >>>>>> a >>>>>> complete shoot into the dark found by rereading the code, but it >>>>>> might >>>>>> actually be the problem. >>>>>> >>>>>> Please give it a try. >>>>>> >>>>>> Going to keep testing in the meantime, >>>>>> Christian. >>>>>> >>>>>> Am 10.05.2014 10:23, schrieb Christian König: >>>>>> >>>>>>>> I see hangs with kernel 3.15 and SI under memory pressure, e.g. >>>>>>>> if >>>>>>>> I boot >>>>>>>> with radeon.vramlimit=256 and then run Xonotic timedemo with >>>>>>>> high >>>>>>>> settings. >>>>>>>> I haven't had a chance to bisect it yet, but it might be a >>>>>>>> similar >>>>>>>> problem. >>>>>>> >>>>>>> >>>>>>> Sounds like the same issue to me. Thx for the good test case. >>>>>>> >>>>>>>> Any idea what is wrong with it? >>>>>>> >>>>>>> >>>>>>> Actually I already wondered that it went so smooth without any >>>>>>> regression >>>>>>> so far, didn't noticed the bug in bugzilla.kernel.org yet. >>>>>>> >>>>>>>> Some of the tests allocate a lot of MSAA textures and the tests >>>>>>>> also >>>>>>>> run in parallel, which creates a lot of memory pressure and >>>>>>>> probably >>>>>>>> causes buffer evictions. >>>>>>> >>>>>>> >>>>>>> Sounds like the underlying problem to me. We probably evict some >>>>>>> part of a >>>>>>> page table without updating the page directory. Going to dig >>>>>>> into >>>>>>> it today, >>>>>>> it's probably just a one liner missing somewhere in the VM code. >>>>>>> >>>>>>> Christian. >>>>>>> >>>>>>> Am 09.05.2014 23:39, schrieb Grigori Goronzy: >>>>>>>> >>>>>>>> >>>>>>>> On 09.05.2014 20:03, Marek Olšák wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> This commit which first appeared in 3.15-rc1 causes hangs on >>>>>>>>> Bonaire: >>>>>>>>> [...] >>>>>>>>> >>>>>>>>> The simplest way to reproduce the hangs is to run piglit with >>>>>>>>> these >>>>>>>>> parameters: >>>>>>>>> -t texelFetch.fs >>>>>>>>> >>>>>>>>> Some of the tests allocate a lot of MSAA textures and the >>>>>>>>> tests >>>>>>>>> also >>>>>>>>> run in parallel, which creates a lot of memory pressure and >>>>>>>>> probably >>>>>>>>> causes buffer evictions. >>>>>>>>> >>>>>>>> I see hangs with kernel 3.15 and SI under memory pressure, e.g. >>>>>>>> if >>>>>>>> I boot >>>>>>>> with radeon.vramlimit=256 and then run Xonotic timedemo with >>>>>>>> high >>>>>>>> settings. >>>>>>>> I haven't had a chance to bisect it yet, but it might be a >>>>>>>> similar >>>>>>>> problem. >>>>>>>> >>>>>>>> Grigori >>>>>>> >>>>>>> >>>>>>> >> _______________________________________________ >> dri-devel mailing list >> dri-devel@lists.freedesktop.org >> http://lists.freedesktop.org/mailman/listinfo/dri-devel