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

Jason Ekstrand jason at jlekstrand.net
Tue Feb 14 04:45:47 UTC 2017


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.

--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
>>
>
>
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