[Mesa-dev] [PATCH v2 2/2] anv: Implement the Sky Lake stencil PMA optimization

Ben Widawsky ben at bwidawsk.net
Fri Feb 3 07:18:50 UTC 2017


On 17-02-02 13:27:05, Jason Ekstrand wrote:
>This improves the performance of Dota 2 on my Sky Lake Skull Canyon
>machine by about 2-3%.
>
>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 6efe4ea..9f88aef 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 271ab3f..6e44bd6 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 Sky Lake 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 Sky Lake 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
>@@ -283,6 +308,126 @@ 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 Sky Lake 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)
> {
>@@ -392,6 +537,7 @@ 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)) {
>@@ -417,6 +563,9 @@ 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_buffer));
>    }
> #endif
>
>diff --git a/src/intel/vulkan/genX_pipeline.c b/src/intel/vulkan/genX_pipeline.c
>index 3f701f3..3087037 100644
>--- a/src/intel/vulkan/genX_pipeline.c
>+++ b/src/intel/vulkan/genX_pipeline.c
>@@ -742,6 +742,7 @@ 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));
>@@ -757,6 +758,7 @@ 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;
>
>@@ -1514,8 +1516,8 @@ 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 ||


s/Sky Lake/Skylake/g

Honestly, I'm a bit surprised you got 2-3%, that's awesome. 


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