[Mesa-dev] [PATCH v2 7/7] anv: Implement the Skylake stencil PMA optimization

Jason Ekstrand jason at jlekstrand.net
Tue Feb 14 18:53:37 UTC 2017


On Tue, Feb 14, 2017 at 10:35 AM, Nanley Chery <nanleychery at gmail.com>
wrote:

> On Mon, Feb 13, 2017 at 08:45:47PM -0800, Jason Ekstrand wrote:
> > On Mon, Feb 13, 2017 at 6:13 PM, Jason Ekstrand <jason at jlekstrand.net>
> > wrote:
> >
> > > On Mon, Feb 13, 2017 at 5:00 PM, Nanley Chery <nanleychery at gmail.com>
> > > wrote:
> > >
> > >> On Fri, Feb 10, 2017 at 11:02:21AM -0800, Jason Ekstrand wrote:
> > >> > This improves the performance of Dota 2 on my Sky Lake Skull Canyon
> > >> > machine by about 2-3%.
> > >> >
> > >>
> > >> This patch looks good. Could we compare our setup and testing in the
> > >> office? I can't reproduce these numbers.
> > >>
> > >
> > > I'll have to do more runs.  At the moment, I'm not seeing a large boost
> > > but I'll get a larger sample size and see if it's visible.
> > >
> >
> > I did a bunch more runs.  It looks like it helps somewhere between 0 and
> > 1%.  Not as much as I saw earlier, but it's definitely non-negative.
> >
>
> Although I've confirmed that the fix is enabled in Dota 2, I'm also not
> seeing any major changes on my SKL GT4. I get positive and negative
> changes in FPS, but it's all < 1% and seemingly noise.
>
> With the commit message updated with your new findings, this patch is
> Reviewed-by: Nanley Chery <nanley.g.chery at intel.com>
>

Here's what I wrote:

    Unfortunately, this doesn't substantially improve the performance of any
    known apps.  With Dota 2 on my Sky Lake gt4, it seems help by somewhere
    between 0% and 1% but there's enough noise that it's hard to get a clear
    picture.



> > --Jason
> >
> >
> > > --Jason
> > >
> > >
> > >> -Nanley
> > >>
> > >> > Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> > >> > ---
> > >> >  src/intel/vulkan/anv_private.h     |   1 +
> > >> >  src/intel/vulkan/gen8_cmd_buffer.c | 157
> > >> ++++++++++++++++++++++++++++++++++++-
> > >> >  src/intel/vulkan/genX_pipeline.c   |   6 +-
> > >> >  3 files changed, 158 insertions(+), 6 deletions(-)
> > >> >
> > >> > diff --git a/src/intel/vulkan/anv_private.h
> > >> b/src/intel/vulkan/anv_private.h
> > >> > index fa6032e..25c9c93 100644
> > >> > --- a/src/intel/vulkan/anv_private.h
> > >> > +++ b/src/intel/vulkan/anv_private.h
> > >> > @@ -1482,6 +1482,7 @@ struct anv_pipeline {
> > >> >     bool                                         writes_depth;
> > >> >     bool                                         depth_test_enable;
> > >> >     bool                                         writes_stencil;
> > >> > +   bool
>  stencil_test_enable;
> > >> >     bool                                         depth_clamp_enable;
> > >> >     bool                                         kill_pixel;
> > >> >
> > >> > diff --git a/src/intel/vulkan/gen8_cmd_buffer.c
> > >> b/src/intel/vulkan/gen8_cmd_buffer.c
> > >> > index 0628f3a..59fd537 100644
> > >> > --- a/src/intel/vulkan/gen8_cmd_buffer.c
> > >> > +++ b/src/intel/vulkan/gen8_cmd_buffer.c
> > >> > @@ -157,16 +157,39 @@ __emit_sf_state(struct anv_cmd_buffer
> *cmd_buffer)
> > >> >  void
> > >> >  genX(cmd_buffer_enable_pma_fix)(struct anv_cmd_buffer *cmd_buffer,
> > >> bool enable)
> > >> >  {
> > >> > -#if GEN_GEN == 8
> > >> >     if (cmd_buffer->state.pma_fix_enabled == enable)
> > >> >        return;
> > >> >
> > >> > +   cmd_buffer->state.pma_fix_enabled = enable;
> > >> > +
> > >> > +   /* According to the Broadwell PIPE_CONTROL documentation,
> software
> > >> should
> > >> > +    * emit a PIPE_CONTROL with the CS Stall and Depth Cache Flush
> bits
> > >> set
> > >> > +    * prior to the LRI.  If stencil buffer writes are enabled,
> then a
> > >> Render
> > >> > +    * Cache Flush is also necessary.
> > >> > +    *
> > >> > +    * The Skylake docs say to use a depth stall rather than a
> command
> > >> > +    * streamer stall.  However, the hardware seems to violently
> > >> disagree.
> > >> > +    * A full command streamer stall seems to be needed in both
> cases.
> > >> > +    */
> > >> >     anv_batch_emit(&cmd_buffer->batch, GENX(PIPE_CONTROL), pc) {
> > >> >        pc.DepthCacheFlushEnable = true;
> > >> >        pc.CommandStreamerStallEnable = true;
> > >> >        pc.RenderTargetCacheFlushEnable = true;
> > >> >     }
> > >> >
> > >> > +#if GEN_GEN == 9
> > >> > +
> > >> > +   uint32_t cache_mode;
> > >> > +   anv_pack_struct(&cache_mode, GENX(CACHE_MODE_0),
> > >> > +                   .STCPMAOptimizationEnable = enable,
> > >> > +                   .STCPMAOptimizationEnableMask = true);
> > >> > +   anv_batch_emit(&cmd_buffer->batch, GENX(MI_LOAD_REGISTER_IMM),
> > >> lri) {
> > >> > +      lri.RegisterOffset   = GENX(CACHE_MODE_0_num);
> > >> > +      lri.DataDWord        = cache_mode;
> > >> > +   }
> > >> > +
> > >> > +#elif GEN_GEN == 8
> > >> > +
> > >> >     uint32_t cache_mode;
> > >> >     anv_pack_struct(&cache_mode, GENX(CACHE_MODE_1),
> > >> >                     .NPPMAFixEnable = enable,
> > >> > @@ -178,18 +201,20 @@ genX(cmd_buffer_enable_pma_fix)(struct
> > >> anv_cmd_buffer *cmd_buffer, bool enable)
> > >> >        lri.DataDWord        = cache_mode;
> > >> >     }
> > >> >
> > >> > +#endif /* GEN_GEN == 8 */
> > >> > +
> > >> >     /* After the LRI, a PIPE_CONTROL with both the Depth Stall and
> > >> Depth Cache
> > >> >      * Flush bits is often necessary.  We do it regardless because
> it's
> > >> easier.
> > >> >      * The render cache flush is also necessary if stencil writes
> are
> > >> enabled.
> > >> > +    *
> > >> > +    * Again, the Skylake docs give a different set of flushes but
> the
> > >> BDW
> > >> > +    * flushes seem to work just as well.
> > >> >      */
> > >> >     anv_batch_emit(&cmd_buffer->batch, GENX(PIPE_CONTROL), pc) {
> > >> >        pc.DepthStallEnable = true;
> > >> >        pc.DepthCacheFlushEnable = true;
> > >> >        pc.RenderTargetCacheFlushEnable = true;
> > >> >     }
> > >> > -
> > >> > -   cmd_buffer->state.pma_fix_enabled = enable;
> > >> > -#endif /* GEN_GEN == 8 */
> > >> >  }
> > >> >
> > >> >  static inline bool
> > >> > @@ -281,6 +306,126 @@ want_depth_pma_fix(struct anv_cmd_buffer
> > >> *cmd_buffer)
> > >> >            wm_prog_data->computed_depth_mode != PSCDEPTH_OFF;
> > >> >  }
> > >> >
> > >> > +static inline bool
> > >> > +want_stencil_pma_fix(struct anv_cmd_buffer *cmd_buffer)
> > >> > +{
> > >> > +   assert(GEN_GEN == 9);
> > >> > +
> > >> > +   /* From the Skylake PRM Vol. 2c CACHE_MODE_1::STC PMA
> Optimization
> > >> Enable:
> > >> > +    *
> > >> > +    *    Clearing this bit will force the STC cache to wait for
> pending
> > >> > +    *    retirement of pixels at the HZ-read stage and do the
> STC-test
> > >> for
> > >> > +    *    Non-promoted, R-computed and Computed depth modes instead
> of
> > >> > +    *    postponing the STC-test to RCPFE.
> > >> > +    *
> > >> > +    *    STC_TEST_EN = 3DSTATE_STENCIL_BUFFER::
> STENCIL_BUFFER_ENABLE
> > >> &&
> > >> > +    *                  3DSTATE_WM_DEPTH_STENCIL::StencilTestEnable
> > >> > +    *
> > >> > +    *    STC_WRITE_EN = 3DSTATE_STENCIL_BUFFER::
> STENCIL_BUFFER_ENABLE
> > >> &&
> > >> > +    *                   (3DSTATE_WM_DEPTH_STENCIL::Stencil Buffer
> > >> Write Enable &&
> > >> > +    *                    3DSTATE_DEPTH_BUFFER::STENCIL_
> WRITE_ENABLE)
> > >> > +    *
> > >> > +    *    COMP_STC_EN = STC_TEST_EN &&
> > >> > +    *                  3DSTATE_PS_EXTRA::
> PixelShaderComputesStencil
> > >> > +    *
> > >> > +    *    SW parses the pipeline states to generate the following
> > >> logical
> > >> > +    *    signal indicating if PMA FIX can be enabled.
> > >> > +    *
> > >> > +    *    STC_PMA_OPT =
> > >> > +    *       3DSTATE_WM::ForceThreadDispatch != 1 &&
> > >> > +    *       !(3DSTATE_RASTER::ForceSampleCount !=
> NUMRASTSAMPLES_0) &&
> > >> > +    *       3DSTATE_DEPTH_BUFFER::SURFACE_TYPE != NULL &&
> > >> > +    *       3DSTATE_DEPTH_BUFFER::HIZ Enable &&
> > >> > +    *       !(3DSTATE_WM::EDSC_Mode == 2) &&
> > >> > +    *       3DSTATE_PS_EXTRA::PixelShaderValid &&
> > >> > +    *       !(3DSTATE_WM_HZ_OP::DepthBufferClear ||
> > >> > +    *         3DSTATE_WM_HZ_OP::DepthBufferResolve ||
> > >> > +    *         3DSTATE_WM_HZ_OP::Hierarchical Depth Buffer Resolve
> > >> Enable ||
> > >> > +    *         3DSTATE_WM_HZ_OP::StencilBufferClear) &&
> > >> > +    *       (COMP_STC_EN || STC_WRITE_EN) &&
> > >> > +    *       ((3DSTATE_PS_EXTRA::PixelShaderKillsPixels ||
> > >> > +    *         3DSTATE_WM::ForceKillPix == ON ||
> > >> > +    *         3DSTATE_PS_EXTRA::oMask Present to RenderTarget ||
> > >> > +    *         3DSTATE_PS_BLEND::AlphaToCoverageEnable ||
> > >> > +    *         3DSTATE_PS_BLEND::AlphaTestEnable ||
> > >> > +    *         3DSTATE_WM_CHROMAKEY::ChromaKeyKillEnable) ||
> > >> > +    *        (3DSTATE_PS_EXTRA::Pixel Shader Computed Depth mode !=
> > >> PSCDEPTH_OFF))
> > >> > +    */
> > >> > +
> > >> > +   /* These are always true:
> > >> > +    *    3DSTATE_WM::ForceThreadDispatch != 1 &&
> > >> > +    *    !(3DSTATE_RASTER::ForceSampleCount != NUMRASTSAMPLES_0)
> > >> > +    */
> > >> > +
> > >> > +   /* We only enable the PMA fix if we know for certain that HiZ is
> > >> enabled.
> > >> > +    * If we don't know whether HiZ is enabled or not, we disable
> the
> > >> PMA fix
> > >> > +    * and there is no harm.
> > >> > +    *
> > >> > +    * (3DSTATE_DEPTH_BUFFER::SURFACE_TYPE != NULL) &&
> > >> > +    * 3DSTATE_DEPTH_BUFFER::HIZ Enable
> > >> > +    */
> > >> > +   if (!cmd_buffer->state.hiz_enabled)
> > >> > +      return false;
> > >> > +
> > >> > +   /* We can't possibly know if HiZ is enabled without the
> framebuffer
> > >> */
> > >> > +   assert(cmd_buffer->state.framebuffer);
> > >> > +
> > >> > +   /* HiZ is enabled so we had better have a depth buffer with HiZ
> */
> > >> > +   const struct anv_image_view *ds_iview =
> > >> > +      anv_cmd_buffer_get_depth_stencil_view(cmd_buffer);
> > >> > +   assert(ds_iview && ds_iview->image->aux_usage ==
> ISL_AUX_USAGE_HIZ);
> > >> > +
> > >> > +   /* 3DSTATE_PS_EXTRA::PixelShaderValid */
> > >> > +   struct anv_pipeline *pipeline = cmd_buffer->state.pipeline;
> > >> > +   if (!anv_pipeline_has_stage(pipeline, MESA_SHADER_FRAGMENT))
> > >> > +      return false;
> > >> > +
> > >> > +   /* !(3DSTATE_WM::EDSC_Mode == 2) */
> > >> > +   const struct brw_wm_prog_data *wm_prog_data =
> > >> get_wm_prog_data(pipeline);
> > >> > +   if (wm_prog_data->early_fragment_tests)
> > >> > +      return false;
> > >> > +
> > >> > +   /* We never use anv_pipeline for HiZ ops so this is trivially
> true:
> > >> > +   *    !(3DSTATE_WM_HZ_OP::DepthBufferClear ||
> > >> > +    *      3DSTATE_WM_HZ_OP::DepthBufferResolve ||
> > >> > +    *      3DSTATE_WM_HZ_OP::Hierarchical Depth Buffer Resolve
> Enable
> > >> ||
> > >> > +    *      3DSTATE_WM_HZ_OP::StencilBufferClear)
> > >> > +    */
> > >> > +
> > >> > +   /* 3DSTATE_STENCIL_BUFFER::STENCIL_BUFFER_ENABLE &&
> > >> > +    * 3DSTATE_WM_DEPTH_STENCIL::StencilTestEnable
> > >> > +    */
> > >> > +   const bool stc_test_en =
> > >> > +      (ds_iview->image->aspects & VK_IMAGE_ASPECT_STENCIL_BIT) &&
> > >> > +      pipeline->stencil_test_enable;
> > >> > +
> > >> > +   /* 3DSTATE_STENCIL_BUFFER::STENCIL_BUFFER_ENABLE &&
> > >> > +    * (3DSTATE_WM_DEPTH_STENCIL::Stencil Buffer Write Enable &&
> > >> > +    *  3DSTATE_DEPTH_BUFFER::STENCIL_WRITE_ENABLE)
> > >> > +    */
> > >> > +   const bool stc_write_en =
> > >> > +      (ds_iview->image->aspects & VK_IMAGE_ASPECT_STENCIL_BIT) &&
> > >> > +      pipeline->writes_stencil;
> > >> > +
> > >> > +   /* STC_TEST_EN && 3DSTATE_PS_EXTRA::PixelShaderComputesStencil
> */
> > >> > +   const bool comp_stc_en = stc_test_en &&
> > >> wm_prog_data->computed_stencil;
> > >> > +
> > >> > +   /* COMP_STC_EN || STC_WRITE_EN */
> > >> > +   if (!(comp_stc_en || stc_write_en))
> > >> > +      return false;
> > >> > +
> > >> > +   /* (3DSTATE_PS_EXTRA::PixelShaderKillsPixels ||
> > >> > +    *  3DSTATE_WM::ForceKillPix == ON ||
> > >> > +    *  3DSTATE_PS_EXTRA::oMask Present to RenderTarget ||
> > >> > +    *  3DSTATE_PS_BLEND::AlphaToCoverageEnable ||
> > >> > +    *  3DSTATE_PS_BLEND::AlphaTestEnable ||
> > >> > +    *  3DSTATE_WM_CHROMAKEY::ChromaKeyKillEnable) ||
> > >> > +    * (3DSTATE_PS_EXTRA::Pixel Shader Computed Depth mode !=
> > >> PSCDEPTH_OFF)
> > >> > +    */
> > >> > +   return pipeline->kill_pixel ||
> > >> > +          wm_prog_data->computed_depth_mode != PSCDEPTH_OFF;
> > >> > +}
> > >> > +
> > >> >  void
> > >> >  genX(cmd_buffer_flush_dynamic_state)(struct anv_cmd_buffer
> > >> *cmd_buffer)
> > >> >  {
> > >> > @@ -390,6 +535,7 @@ genX(cmd_buffer_flush_dynamic_state)(struct
> > >> anv_cmd_buffer *cmd_buffer)
> > >> >     }
> > >> >
> > >> >     if (cmd_buffer->state.dirty & (ANV_CMD_DIRTY_PIPELINE |
> > >> > +                                  ANV_CMD_DIRTY_RENDER_TARGETS |
> > >> >                                    ANV_CMD_DIRTY_DYNAMIC_STENCIL_
> COMPARE_MASK
> > >> |
> > >> >                                    ANV_CMD_DIRTY_DYNAMIC_STENCIL_
> WRITE_MASK
> > >> |
> > >> >                                    ANV_CMD_DIRTY_DYNAMIC_STENCIL_
> REFERENCE))
> > >> {
> > >> > @@ -415,6 +561,9 @@ genX(cmd_buffer_flush_dynamic_state)(struct
> > >> anv_cmd_buffer *cmd_buffer)
> > >> >
> > >> >        anv_batch_emit_merge(&cmd_buffer->batch, dwords,
> > >> >                             pipeline->gen9.wm_depth_stencil);
> > >> > +
> > >> > +      genX(cmd_buffer_enable_pma_fix)(cmd_buffer,
> > >> > +
> want_stencil_pma_fix(cmd_buffe
> > >> r));
> > >> >     }
> > >> >  #endif
> > >> >
> > >> > diff --git a/src/intel/vulkan/genX_pipeline.c
> > >> b/src/intel/vulkan/genX_pipeline.c
> > >> > index d2af8b9..3b0ae08 100644
> > >> > --- a/src/intel/vulkan/genX_pipeline.c
> > >> > +++ b/src/intel/vulkan/genX_pipeline.c
> > >> > @@ -784,6 +784,7 @@ emit_ds_state(struct anv_pipeline *pipeline,
> > >> >         * to make sure it's initialized to something useful.
> > >> >         */
> > >> >        pipeline->writes_stencil = false;
> > >> > +      pipeline->stencil_test_enable = false;
> > >> >        pipeline->writes_depth = false;
> > >> >        pipeline->depth_test_enable = false;
> > >> >        memset(depth_stencil_dw, 0, sizeof(depth_stencil_dw));
> > >> > @@ -799,6 +800,7 @@ emit_ds_state(struct anv_pipeline *pipeline,
> > >> >
> > >> >     VkPipelineDepthStencilStateCreateInfo info = *pCreateInfo;
> > >> >     sanitize_ds_state(&info, &pipeline->writes_stencil, ds_aspects);
> > >> > +   pipeline->stencil_test_enable = info.stencilTestEnable;
> > >> >     pipeline->writes_depth = info.depthWriteEnable;
> > >> >     pipeline->depth_test_enable = info.depthTestEnable;
> > >> >
> > >> > @@ -1556,8 +1558,8 @@ compute_kill_pixel(struct anv_pipeline
> *pipeline,
> > >> >     const struct brw_wm_prog_data *wm_prog_data =
> > >> get_wm_prog_data(pipeline);
> > >> >
> > >> >     /* This computes the KillPixel portion of the computation for
> > >> whether or
> > >> > -    * not we want to enable the PMA fix on gen8.  It's given by
> this
> > >> chunk of
> > >> > -    * the giant formula:
> > >> > +    * not we want to enable the PMA fix on gen8 or gen9.  It's
> given
> > >> by this
> > >> > +    * chunk of the giant formula:
> > >> >      *
> > >> >      *    (3DSTATE_PS_EXTRA::PixelShaderKillsPixels ||
> > >> >      *     3DSTATE_PS_EXTRA::oMask Present to RenderTarget ||
> > >> > --
> > >> > 2.5.0.400.gff86faf
> > >> >
> > >> > _______________________________________________
> > >> > mesa-dev mailing list
> > >> > mesa-dev at lists.freedesktop.org
> > >> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> > >>
> > >
> > >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20170214/282c9096/attachment-0001.html>


More information about the mesa-dev mailing list