On Thu, May 21, 2015 at 01:18:44PM -0700, Jesse Barnes wrote: > On 05/19/2015 10:32 AM, ville.syrjala@xxxxxxxxxxxxxxx wrote: > > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > > > GTT caching was disabled by default on gen8 due to not working with > > big pages. Some information suggests that it got fixed, but still > > GTT caching has been left disabled by default. Or could be it just > > meant that the default was changed to off, and hence the problem > > got solved. > > > > Enable GTT caching in the hopes of some performance increase. > > Whether or not the big pages issue has been fixed is irrelevant > > at this stage since we don't use big pages. > > > > This gives me a 1-2% improvement in xonotic on my BSW. Haven't tried > > BDW, but supposedly it has larger TLBs so might not benefit as much. > > On HSW GTT caching is enabled by default. > > > > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > --- > > drivers/gpu/drm/i915/i915_reg.h | 2 ++ > > drivers/gpu/drm/i915/intel_pm.c | 13 +++++++++++++ > > 2 files changed, 15 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h > > index 84af255..90640d5 100644 > > --- a/drivers/gpu/drm/i915/i915_reg.h > > +++ b/drivers/gpu/drm/i915/i915_reg.h > > @@ -1461,6 +1461,8 @@ enum skl_disp_power_wells { > > #define RING_HWS_PGA(base) ((base)+0x80) > > #define RING_HWS_PGA_GEN6(base) ((base)+0x2080) > > > > +#define HSW_GTT_CACHE_EN 0x4024 > > +#define GTT_CACHE_EN_ALL 0xF0007FFF > > #define GEN7_WR_WATERMARK 0x4028 > > #define GEN7_GFX_PRIO_CTRL 0x402C > > #define ARB_MODE 0x4030 > > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c > > index 5ec56b6..58517a50 100644 > > --- a/drivers/gpu/drm/i915/intel_pm.c > > +++ b/drivers/gpu/drm/i915/intel_pm.c > > @@ -6205,6 +6205,13 @@ static void broadwell_init_clock_gating(struct drm_device *dev) > > I915_WRITE(GEN8_L3SQCREG1, BDW_WA_L3SQCREG1_DEFAULT); > > I915_WRITE(GEN7_MISCCPCTL, misccpctl); > > > > + /* > > + * WaGttCachingOffByDefault:bdw > > + * GTT cache may not work with big pages, so if those > > + * are ever enabled GTT cache may need to be disabled. > > + */ > > + I915_WRITE(HSW_GTT_CACHE_EN, GTT_CACHE_EN_ALL); > > + > > lpt_init_clock_gating(dev); > > } > > > > @@ -6480,6 +6487,12 @@ static void cherryview_init_clock_gating(struct drm_device *dev) > > /* WaDisableSDEUnitClockGating:chv */ > > I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) | > > GEN8_SDEUNIT_CLOCK_GATE_DISABLE); > > + > > + /* > > + * GTT cache may not work with big pages, so if those > > + * are ever enabled GTT cache may need to be disabled. > > + */ > > + I915_WRITE(HSW_GTT_CACHE_EN, GTT_CACHE_EN_ALL); > > } > > > > static void g4x_init_clock_gating(struct drm_device *dev) > > > > Looks ok to me; I guess testing will be the real review here. Just aside: If you think the real test for a patch is the real world imo an important part of the review work is to make sure we do have that testing coverage. We have a few igts that specifically exercise gtt tlb issues (from previous generations), so I think we're covered here. > Reviewed-by: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx> Merged all three, thanks for patches&review. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx