| Message ID | cover.1658924372.git.mchehab@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | drm/i915: reduce TLB performance regressions | expand |
Hi Mauro, Pushed in drm-intel-gt-next. Thanks, Andi On Wed, Jul 27, 2022 at 02:29:50PM +0200, Mauro Carvalho Chehab wrote: > Doing TLB invalidation cause performance regressions, like: > [424.370996] i915 0000:00:02.0: [drm] *ERROR* rcs0 TLB invalidation did not complete in 4ms! > > As reported at: > https://gitlab.freedesktop.org/drm/intel/-/issues/6424 > > as this is an expensive operation. So, reduce the need of it by: > - checking if the engine is awake; > - checking if the engine is not wedged; > - batching operations. > > Additionally, add a workaround for a known hardware issue on some GPUs. > > In order to double-check that this series won't be introducing any regressions, > I used this new IGT test: > > https://patchwork.freedesktop.org/patch/495684/?series=106757&rev=1 > > Checking the results for 3 different patchsets, on Broadwell: > > 1) On the top of drm-tip (2022y-07m-14d-08h-35m-36) - e. g. with TLB > invalidation and serialization patches: > > $ sudo build/tests/gem_exec_tlb|grep Subtest > Subtest close-clear: SUCCESS (10.490s) > Subtest madv-clear: SUCCESS (10.484s) > Subtest u-unmap-clear: SUCCESS (10.527s) > Subtest u-shrink-clear: SUCCESS (10.506s) > Subtest close-dumb: SUCCESS (10.165s) > Subtest madv-dumb: SUCCESS (10.177s) > Subtest u-unmap-dumb: SUCCESS (10.172s) > Subtest u-shrink-dumb: SUCCESS (10.172s) > > 2) With the new version of the batch TLB invalidation patches from this series: > > $ sudo build/tests/gem_exec_tlb|grep Subtest > Subtest close-clear: SUCCESS (10.483s) > Subtest madv-clear: SUCCESS (10.495s) > Subtest u-unmap-clear: SUCCESS (10.545s) > Subtest u-shrink-clear: SUCCESS (10.508s) > Subtest close-dumb: SUCCESS (10.172s) > Subtest madv-dumb: SUCCESS (10.169s) > Subtest u-unmap-dumb: SUCCESS (10.174s) > Subtest u-shrink-dumb: SUCCESS (10.176s) > > 3) Changing the TLB invalidation routine to do nothing[1]: > > $ sudo ~/freedesktop-igt/build/tests/gem_exec_tlb|grep Subtest > (gem_exec_tlb:1958) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > (gem_exec_tlb:1958) CRITICAL: Failed assertion: !sq > (gem_exec_tlb:1958) CRITICAL: Found deadbeef in a new (clear) buffer after 3 tries! > (gem_exec_tlb:1956) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > (gem_exec_tlb:1956) CRITICAL: Failed assertion: !sq > (gem_exec_tlb:1956) CRITICAL: Found deadbeef in a new (clear) buffer after 89 tries! > (gem_exec_tlb:1957) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > (gem_exec_tlb:1957) CRITICAL: Failed assertion: !sq > (gem_exec_tlb:1957) CRITICAL: Found deadbeef in a new (clear) buffer after 256 tries! > (gem_exec_tlb:1960) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > (gem_exec_tlb:1960) CRITICAL: Failed assertion: !sq > (gem_exec_tlb:1960) CRITICAL: Found deadbeef in a new (clear) buffer after 845 tries! > (gem_exec_tlb:1961) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > (gem_exec_tlb:1961) CRITICAL: Failed assertion: !sq > (gem_exec_tlb:1961) CRITICAL: Found deadbeef in a new (clear) buffer after 1138 tries! > (gem_exec_tlb:1954) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > (gem_exec_tlb:1954) CRITICAL: Failed assertion: !sq > (gem_exec_tlb:1954) CRITICAL: Found deadbeef in a new (clear) buffer after 1359 tries! > (gem_exec_tlb:1955) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > (gem_exec_tlb:1955) CRITICAL: Failed assertion: !sq > (gem_exec_tlb:1955) CRITICAL: Found deadbeef in a new (clear) buffer after 1794 tries! > (gem_exec_tlb:1959) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > (gem_exec_tlb:1959) CRITICAL: Failed assertion: !sq > (gem_exec_tlb:1959) CRITICAL: Found deadbeef in a new (clear) buffer after 2139 tries! > Dynamic subtest smem0 failed. > **** DEBUG **** > (gem_exec_tlb:1944) DEBUG: 2M hole:200000 contains poison:6b6b6b6b > (gem_exec_tlb:1944) DEBUG: Running writer for 200000 at 300000 on bcs0 > (gem_exec_tlb:1944) DEBUG: Closing hole:200000 on rcs0, sample:deadbeef > (gem_exec_tlb:1944) DEBUG: Rechecking hole:200000, sample:6b6b6b6b > **** END **** > Subtest close-clear: FAIL (10.434s) > Subtest madv-clear: SUCCESS (10.479s) > Subtest u-unmap-clear: SUCCESS (10.512s) > > In summary, the test does properly detect fail when TLB cache invalidation doesn't happen, > as shown at result (3). It also shows that both current drm-tip and drm-tip with this series > applied don't have TLB invalidation cache issues. > > [1] I applied this patch on the top of drm-tip: > > diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c > index 68c2b0d8f187..0aefcd7be5e9 100644 > --- a/drivers/gpu/drm/i915/gt/intel_gt.c > +++ b/drivers/gpu/drm/i915/gt/intel_gt.c > @@ -930,0 +931,3 @@ void intel_gt_invalidate_tlbs(struct intel_gt *gt) > + // HACK: don't do TLB invalidations!!! > + return; > + > > Regards, > Mauro > > Chris Wilson (4): > drm/i915/gt: Ignore TLB invalidations on idle engines > drm/i915/gt: Invalidate TLB of the OA unit at TLB invalidations > drm/i915/gt: Skip TLB invalidations once wedged > drm/i915/gt: Batch TLB invalidations > > Mauro Carvalho Chehab (2): > drm/i915/gt: document with_intel_gt_pm_if_awake() > drm/i915/gt: describe the new tlb parameter at i915_vma_resource > > .../gpu/drm/i915/gem/i915_gem_object_types.h | 3 +- > drivers/gpu/drm/i915/gem/i915_gem_pages.c | 25 +++--- > drivers/gpu/drm/i915/gt/intel_gt.c | 77 +++++++++++++++---- > drivers/gpu/drm/i915/gt/intel_gt.h | 12 ++- > drivers/gpu/drm/i915/gt/intel_gt_pm.h | 11 +++ > drivers/gpu/drm/i915/gt/intel_gt_types.h | 18 ++++- > drivers/gpu/drm/i915/gt/intel_ppgtt.c | 8 +- > drivers/gpu/drm/i915/i915_vma.c | 33 ++++++-- > drivers/gpu/drm/i915/i915_vma.h | 1 + > drivers/gpu/drm/i915/i915_vma_resource.c | 9 ++- > drivers/gpu/drm/i915/i915_vma_resource.h | 6 +- > 11 files changed, 163 insertions(+), 40 deletions(-) > > -- > 2.36.1 >
Hi Andi, On Thu, 28 Jul 2022 14:08:11 +0200 Andi Shyti <andi.shyti@linux.intel.com> wrote: > Hi Mauro, > > Pushed in drm-intel-gt-next. Thank you! I submitted two additional patches moving the TLB code into its own file, and adding the documentation for it, as agreed during patch 5/6 review: https://patchwork.freedesktop.org/series/106806/ That should make easier to maintain TLB-related code and have such functions properly documented. Regards, Mauro > > Thanks, > Andi > > On Wed, Jul 27, 2022 at 02:29:50PM +0200, Mauro Carvalho Chehab wrote: > > Doing TLB invalidation cause performance regressions, like: > > [424.370996] i915 0000:00:02.0: [drm] *ERROR* rcs0 TLB invalidation did not complete in 4ms! > > > > As reported at: > > https://gitlab.freedesktop.org/drm/intel/-/issues/6424 > > > > as this is an expensive operation. So, reduce the need of it by: > > - checking if the engine is awake; > > - checking if the engine is not wedged; > > - batching operations. > > > > Additionally, add a workaround for a known hardware issue on some GPUs. > > > > In order to double-check that this series won't be introducing any regressions, > > I used this new IGT test: > > > > https://patchwork.freedesktop.org/patch/495684/?series=106757&rev=1 > > > > Checking the results for 3 different patchsets, on Broadwell: > > > > 1) On the top of drm-tip (2022y-07m-14d-08h-35m-36) - e. g. with TLB > > invalidation and serialization patches: > > > > $ sudo build/tests/gem_exec_tlb|grep Subtest > > Subtest close-clear: SUCCESS (10.490s) > > Subtest madv-clear: SUCCESS (10.484s) > > Subtest u-unmap-clear: SUCCESS (10.527s) > > Subtest u-shrink-clear: SUCCESS (10.506s) > > Subtest close-dumb: SUCCESS (10.165s) > > Subtest madv-dumb: SUCCESS (10.177s) > > Subtest u-unmap-dumb: SUCCESS (10.172s) > > Subtest u-shrink-dumb: SUCCESS (10.172s) > > > > 2) With the new version of the batch TLB invalidation patches from this series: > > > > $ sudo build/tests/gem_exec_tlb|grep Subtest > > Subtest close-clear: SUCCESS (10.483s) > > Subtest madv-clear: SUCCESS (10.495s) > > Subtest u-unmap-clear: SUCCESS (10.545s) > > Subtest u-shrink-clear: SUCCESS (10.508s) > > Subtest close-dumb: SUCCESS (10.172s) > > Subtest madv-dumb: SUCCESS (10.169s) > > Subtest u-unmap-dumb: SUCCESS (10.174s) > > Subtest u-shrink-dumb: SUCCESS (10.176s) > > > > 3) Changing the TLB invalidation routine to do nothing[1]: > > > > $ sudo ~/freedesktop-igt/build/tests/gem_exec_tlb|grep Subtest > > (gem_exec_tlb:1958) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > > (gem_exec_tlb:1958) CRITICAL: Failed assertion: !sq > > (gem_exec_tlb:1958) CRITICAL: Found deadbeef in a new (clear) buffer after 3 tries! > > (gem_exec_tlb:1956) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > > (gem_exec_tlb:1956) CRITICAL: Failed assertion: !sq > > (gem_exec_tlb:1956) CRITICAL: Found deadbeef in a new (clear) buffer after 89 tries! > > (gem_exec_tlb:1957) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > > (gem_exec_tlb:1957) CRITICAL: Failed assertion: !sq > > (gem_exec_tlb:1957) CRITICAL: Found deadbeef in a new (clear) buffer after 256 tries! > > (gem_exec_tlb:1960) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > > (gem_exec_tlb:1960) CRITICAL: Failed assertion: !sq > > (gem_exec_tlb:1960) CRITICAL: Found deadbeef in a new (clear) buffer after 845 tries! > > (gem_exec_tlb:1961) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > > (gem_exec_tlb:1961) CRITICAL: Failed assertion: !sq > > (gem_exec_tlb:1961) CRITICAL: Found deadbeef in a new (clear) buffer after 1138 tries! > > (gem_exec_tlb:1954) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > > (gem_exec_tlb:1954) CRITICAL: Failed assertion: !sq > > (gem_exec_tlb:1954) CRITICAL: Found deadbeef in a new (clear) buffer after 1359 tries! > > (gem_exec_tlb:1955) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > > (gem_exec_tlb:1955) CRITICAL: Failed assertion: !sq > > (gem_exec_tlb:1955) CRITICAL: Found deadbeef in a new (clear) buffer after 1794 tries! > > (gem_exec_tlb:1959) CRITICAL: Test assertion failure function check_bo, file ../tests/i915/gem_exec_tlb.c:384: > > (gem_exec_tlb:1959) CRITICAL: Failed assertion: !sq > > (gem_exec_tlb:1959) CRITICAL: Found deadbeef in a new (clear) buffer after 2139 tries! > > Dynamic subtest smem0 failed. > > **** DEBUG **** > > (gem_exec_tlb:1944) DEBUG: 2M hole:200000 contains poison:6b6b6b6b > > (gem_exec_tlb:1944) DEBUG: Running writer for 200000 at 300000 on bcs0 > > (gem_exec_tlb:1944) DEBUG: Closing hole:200000 on rcs0, sample:deadbeef > > (gem_exec_tlb:1944) DEBUG: Rechecking hole:200000, sample:6b6b6b6b > > **** END **** > > Subtest close-clear: FAIL (10.434s) > > Subtest madv-clear: SUCCESS (10.479s) > > Subtest u-unmap-clear: SUCCESS (10.512s) > > > > In summary, the test does properly detect fail when TLB cache invalidation doesn't happen, > > as shown at result (3). It also shows that both current drm-tip and drm-tip with this series > > applied don't have TLB invalidation cache issues. > > > > [1] I applied this patch on the top of drm-tip: > > > > diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c > > index 68c2b0d8f187..0aefcd7be5e9 100644 > > --- a/drivers/gpu/drm/i915/gt/intel_gt.c > > +++ b/drivers/gpu/drm/i915/gt/intel_gt.c > > @@ -930,0 +931,3 @@ void intel_gt_invalidate_tlbs(struct intel_gt *gt) > > + // HACK: don't do TLB invalidations!!! > > + return; > > + > > > > Regards, > > Mauro > > > > Chris Wilson (4): > > drm/i915/gt: Ignore TLB invalidations on idle engines > > drm/i915/gt: Invalidate TLB of the OA unit at TLB invalidations > > drm/i915/gt: Skip TLB invalidations once wedged > > drm/i915/gt: Batch TLB invalidations > > > > Mauro Carvalho Chehab (2): > > drm/i915/gt: document with_intel_gt_pm_if_awake() > > drm/i915/gt: describe the new tlb parameter at i915_vma_resource > > > > .../gpu/drm/i915/gem/i915_gem_object_types.h | 3 +- > > drivers/gpu/drm/i915/gem/i915_gem_pages.c | 25 +++--- > > drivers/gpu/drm/i915/gt/intel_gt.c | 77 +++++++++++++++---- > > drivers/gpu/drm/i915/gt/intel_gt.h | 12 ++- > > drivers/gpu/drm/i915/gt/intel_gt_pm.h | 11 +++ > > drivers/gpu/drm/i915/gt/intel_gt_types.h | 18 ++++- > > drivers/gpu/drm/i915/gt/intel_ppgtt.c | 8 +- > > drivers/gpu/drm/i915/i915_vma.c | 33 ++++++-- > > drivers/gpu/drm/i915/i915_vma.h | 1 + > > drivers/gpu/drm/i915/i915_vma_resource.c | 9 ++- > > drivers/gpu/drm/i915/i915_vma_resource.h | 6 +- > > 11 files changed, 163 insertions(+), 40 deletions(-) > > > > -- > > 2.36.1 > >