On Mon, Jan 30, 2017 at 12:24:45PM -0800, Francisco Jerez wrote:
> The WaDisableLSQCROPERFforOCL workaround has the side effect of
> disabling an L3SQ optimization that has huge performance implications
> and is unlikely to be necessary for the correct functioning of usual
> graphic workloads. Userspace is free to re-enable the workaround on
> demand, and is generally in a better position to determine whether the
> workaround is necessary than the DRM is (e.g. only during the
> execution of compute kernels that rely on both L3 fences and HDC R/W
> requests).
>
> The same workaround seems to apply to BDW (at least to production
> stepping G1) and SKL as well (the internal workaround database claims
> that it does for all steppings, while the BSpec workaround table only
> mentions pre-production steppings), but the DRM doesn't do anything
> beyond whitelisting the L3SQCREG4 register so userspace can enable it
> when it sees fit. Do the same on KBL platforms.
>
> Improves performance of the GFXBench4 gl_manhattan31 benchmark by 60%,
> and gl_4 (AKA car chase) by 14% on a KBL GT2 running Mesa master --
> This is followed by a regression of 35% and 10% respectively for the
> same benchmarks and platform caused by my recent patch series
> switching userspace to use the dataport constant cache instead of the
> sampler to implement uniform pull constant loads, which caused us to
> hit more heavily the L3 cache (and on platforms other than KBL had the
> opposite effect of improving performance of the same two benchmarks).
> The overall effect on KBL of this change combined with the recent
> userspace change is respectively 4.6% and 2.6%. SynMark2 OglShMapPcf
> was affected by the constant cache changes (though it improved as it
> did on other platforms rather than regressing), but is not
> significantly affected by this patch (with statistical significance of
> 5% and sample size 20).
>
> v2: Drop some more code to avoid unused variable warning.
>
> Fixes: 738fa1b3123f ("drm/i915/kbl: Add WaDisableLSQCROPERFforOCL")
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99256
> Signed-off-by: Francisco Jerez <currojerez@xxxxxxxxxx>
> Cc: Matthew Auld <matthew.william.auld@xxxxxxxxx>
> Cc: Eero Tamminen <eero.t.tamminen@xxxxxxxxx>
> Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
> Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
> Cc: beignet@xxxxxxxxxxxxxxxxxxxxx
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.7+
> Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
> [Removed double Fixes tag]
> Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
> Link: http://patchwork.freedesktop.org/patch/msgid/1484217894-20505-1-git-send-email-mika.kuoppala@xxxxxxxxx
> (cherry picked from commit 8726f2faa371514fba2f594d799db95203dfeee0)
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> [ Francisco Jerez: Rebase on v4.9 branch. ]
> Signed-off-by: Francisco Jerez <currojerez@xxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_lrc.c | 3 +--
> drivers/gpu/drm/i915/intel_ringbuffer.c | 8 --------
> 2 files changed, 1 insertion(+), 10 deletions(-)
What is the commit id of this patch in Linus's tree?
thanks,
greg k-h
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