hi dri-devel,
Im pretty new in this particular playground. Im using this to send, is it too spammy ? too --to ? git send-email --dry-run \ --to-cmd='scripts/get_maintainer.pl --no-rolestats v3-000*.patch' \ --to=jbaron@akamai.com v3-000*.patch
drm_debug_enabled() is called a lot (by drm_dev_dbg) to do unlikely bit-tests to selectively enable debug printing; this is a good job for dynamic-debug, IFF it is built with JUMP_LABEL.
This patchset enables the use of dynamic-debug to avoid those drm_debug_enabled() overheads, if CONFIG_DRM_USE_DYNAMIC_DEBUG=y.
v3: fixes missed SOB, && on BOL, commit-log tweaks reordered patches, 1 is comment, 2 is whitespace. dropped RFC, to see what happens. v2: https://lore.kernel.org/lkml/20210711055003.528167-1-jim.cromie@gmail.com/ v1: https://lore.kernel.org/lkml/20201204035318.332419-1-jim.cromie@gmail.com/
Doing so creates many new pr_debug callsites, otherwise i915 has ~120 prdbgs, and drm has just 1;
bash-5.1# modprobe i915 dyndbg: 8 debug prints in module video dyndbg: 305 debug prints in module drm dyndbg: 207 debug prints in module drm_kms_helper dyndbg: 2 debug prints in module ttm dyndbg: 1720 debug prints in module i915
On amdgpu, enabling it adds ~3200 prdbgs, currently at 56 bytes each. So CONFIG_DRM_USE_DYNAMIC_DEBUG=y affects resource requirements.
Im running this patchset bare-metal on an i915 laptop & an amdgpu desktop (both as loadable modules). I booted the amdgpu box with:
BOOT_IMAGE=(hd2,gpt2)/vmlinuz-5.13.0-dd7-13692-g8def25788f56 \ root=UUID=mumble ro \ rootflags=subvol=root00 rhgb \ dynamic_debug.verbose=3 main.dyndbg=+p \ amdgpu.debug=1 amdgpu.test=1 \ "amdgpu.dyndbg=format ^[ +p"
That last line enables ~1700 prdbg callsites with a format like '[DML' etc at boot, and amdgpu.test=1 triggers 3 minutes of tests, causing ~76k prdbgs in 409 seconds, before I turned them off with:
echo module amdgpu -p > /proc/dynamic_debug/control
This is on top of master @ v5.14-rc1 Should I rebase onto something else ?
Jim Cromie (5): drm/print: fixup spelling in a comment drm_print.h: rewrap __DRM_DEFINE_DBG_RATELIMITED macro drm/print: RFC add choice to use dynamic debug in drm-debug drm/print: move conditional deref into macro defn i915: map gvt pr_debug categories to bits in parameters/debug_gvt
Note: 3/5, 5/5 have bits that are here for POC, but belong in dynamic_debug.c.
drivers/gpu/drm/Kconfig | 13 ++++ drivers/gpu/drm/drm_print.c | 75 +++++++++++++++++- drivers/gpu/drm/i915/gvt/Makefile | 4 + drivers/gpu/drm/i915/i915_params.c | 76 +++++++++++++++++++ include/drm/drm_print.h | 117 ++++++++++++++++++++--------- 5 files changed, 247 insertions(+), 38 deletions(-)