<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Fri, Feb 10, 2017 at 4:47 PM, Nanley Chery <<a href="mailto:nanleychery@gmail.com" target="_blank">nanleychery@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5">On Fri, Feb 10, 2017 at 03:21:38PM -0800, Jason Ekstrand wrote: > On Fri, Feb 10, 2017 at 2:55 PM, Nanley Chery <<a href="mailto:nanleychery@gmail.com">nanleychery@gmail.com</a>> wrote: > > > On Fri, Feb 10, 2017 at 11:02:19AM -0800, Jason Ekstrand wrote: > > > It's a bit hard to measure because it almost gets lost in the noise, > > > but this seemed to help Dota 2 by a percent or two on my Broadwell > > > GT3e desktop. > > > > > > Reviewed-by: Lionel Landwerlin <<a href="mailto:lionel.g.landwerlin@intel.com">lionel.g.landwerlin@intel.com</a>> > > > --- > > > src/intel/vulkan/genX_pipeline.c | 171 ++++++++++++++++++++++++++++++ > > +-------- > > > 1 file changed, 137 insertions(+), 34 deletions(-) > > > > > > diff --git a/src/intel/vulkan/genX_pipeline.c b/src/intel/vulkan/genX_ > > pipeline.c > > > index 71b9e30..d2af8b9 100644 > > > --- a/src/intel/vulkan/genX_pipeline.c > > > +++ b/src/intel/vulkan/genX_pipeline.c > > > @@ -638,6 +638,133 @@ static const uint32_t vk_to_gen_stencil_op[] = { > > > [VK_STENCIL_OP_DECREMENT_AND_WRAP] = STENCILOP_DECR, > > > }; > > > > > > +static bool > > > +may_write_stencil_face(const VkStencilOpState *face, > > > + VkCompareOp depthCompareOp) > > > +{ > > > > This function triggers some false negatives. One example is > > > > face->compareOp == VK_COMPARE_OP_GREATER && > > face->depthFailOp == VK_STENCIL_OP_KEEP && > > face->passOp == VK_STENCIL_OP_KEEP && > > face->failOp == VK_STENCIL_OP_INVERT && > > depthCompareOp == don't care; > > > > This function returns false even though a stencil write occurs if the > > stencil test results in a fail. > > > > The possible input combinations that affect writing to stencil can be > > divided up into 10 sets. > > > > s = stencil compare op > > d = depth compare op > > df = depth fail op > > sf = stencil fail op > > sp = stencil pass op > > > > s.Always | !s.Always > > d.Never | !d.Never | s.Never | > > | d.Always | | | > > !keep | | | | > > | | | | > > ------------|----------|------|--------------|-------------- > > | | | | > > keep df.Keep | sp.Keep | | sf.Keep | > > | | | | > > | | | | > > > > We know that stencil won't be written if the function inputs land us in > > 3 of these sets (denoted by the *.Keep's above). I think this function > > would be easier to understand if it determined if we fell in one of the > > 3 instead of the 7. How about something like this: > > > > static bool > > wont_write_stencil_face(const VkStencilOpState *face, > > VkCompareOp depthCompareOp) > > { > > if (face->compareOp == VK_COMPARE_OP_NEVER && > > face->failOp == VK_STENCIL_OP_KEEP) > > return true; > > > > if (face->compareOp == VK_COMPARE_OP_ALWAYS) { > > if (depthCompareOp == VK_COMPARE_OP_NEVER && > > face->depthFailOp == VK_STENCIL_OP_KEEP) > > return true; > > if (depthCompareOp == VK_COMPARE_OP_ALWAYS && > > face->passOp == VK_STENCIL_OP_KEEP) > > return true; > > } > > > > This covers a lot fewer cases. For instance, if all of the stencil ops are > VK_STENCIL_OP_KEEP but compareOp == VK_COMPARE_OP_GREATER, your function > will claim that it writes stencil even though it clearly doesn't. > </div></div>You're right, there are more than 3/10 cases in which we know we won't be writing to the stencil face. Here's another attempt at an easier-to-understand function: </blockquote> </div><div class="gmail_quote">This function gets it wrong in the following case: </div><div class="gmail_quote">compareOp == VK_COMPARE_OP_GREATER </div><div class="gmail_quote">failOp == VK_STENCIL_OP_KEEP </div><div class="gmail_quote">passOp == VK_STENCIL_OP_REPLACE </div><div class="gmail_quote">depthFailOp == VK_STENCIL_OP_REPLACE </div><div class="gmail_quote">In this case, st_may_fail == true but sfo_not_keep == false so it returns false. However, it can clearly still write stencil if the stencil test passes. </div><div class="gmail_quote">--Jason </div><div class="gmail_quote"><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> static bool may_write_stencil_face(const VkStencilOpState *face, VkCompareOp depthCompareOp) { const bool spo_not_keep = face->passOp != VK_STENCIL_OP_KEEP; const bool sfo_not_keep = face->failOp != VK_STENCIL_OP_KEEP; const bool dfo_not_keep = face->depthFailOp != VK_STENCIL_OP_KEEP; const bool dt_may_fail = depthCompareOp != VK_COMPARE_OP_ALWAYS; const bool st_may_fail = face->compareOp != VK_COMPARE_OP_ALWAYS; if (st_may_fail) { /* If the stencil test may fail, but the fail op is not keep, we might be * writing to the stencil face. */ if (sfo_not_keep) return true; } else { /* If the stencil test will pass, but the pass op is not keep, we might * be writing to the stencil face. */ if (spo_not_keep) return true; /* If the stencil test will pass, and the depth test may fail, but the * depth fail op is not keep, we might be writing to the stencil face. */ if (dt_may_fail && dfo_not_keep) return true; } return false; } -Nanley > <div class="HOEnZb"><div class="h5">> > return false; > > } > > > > -Nanley > > > > > + /* If compareOp is ALWAYS then the stencil test will never fail and > > we can > > > + * ignore failOp. If it's not ALWAYS and failOp is not KEEP, we may > > write > > > + * stencil. > > > + */ > > > + if (face->compareOp != VK_COMPARE_OP_ALWAYS && > > > + face->failOp != VK_STENCIL_OP_KEEP) > > > + return true; > > > + > > > + > > > + /* If the compareOp is NEVER then the stencil test will never pass > > and the > > > + * passOp and depthFailOp don't matter. If compareOp isn't NEVER, > > then we > > > + * need to take them into account. > > > + */ > > > + if (face->compareOp != VK_COMPARE_OP_NEVER) { > > > + /* If depthOp is NEVER then passOp doesn't matter. */ > > > + if (depthCompareOp != VK_COMPARE_OP_NEVER && > > > + face->passOp != VK_STENCIL_OP_KEEP) > > > + return true; > > > + > > > + /* If depthOp is ALWAYS then depthFailOp doesn't matter. */ > > > + if (depthCompareOp != VK_COMPARE_OP_ALWAYS && > > > + face->depthFailOp != VK_STENCIL_OP_KEEP) > > > + return true; > > > + } > > > + > > > + return false; > > > +} > > > + > > > +/* Intel hardware is fairly sensitive to whether or not depth/stencil > > writes > > > + * are enabled. In the presence of discards, it's fairly easy to get > > into the > > > + * non-promoted case which means a fairly big performance hit. From > > the Iron > > > + * Lake PRM, Vol 2, pt. 1, section 8.4.3.2, "Early Depth Test Cases": > > > + * > > > + * "Non-promoted depth (N) is active whenever the depth test can be > > done > > > + * early but it cannot determine whether or not to write source > > depth to > > > + * the depth buffer, therefore the depth write must be performed > > post pixel > > > + * shader. This includes cases where the pixel shader can kill > > pixels, > > > + * including via sampler chroma key, as well as cases where the > > alpha test > > > + * function is enabled, which kills pixels based on a programmable > > alpha > > > + * test. In this case, even if the depth test fails, the pixel > > cannot be > > > + * killed if a stencil write is indicated. Whether or not the > > stencil write > > > + * happens depends on whether or not the pixel is killed later. In > > these > > > + * cases if stencil test fails and stencil writes are off, the > > pixels can > > > + * also be killed early. If stencil writes are enabled, the pixels > > must be > > > + * treated as Computed depth (described above)." > > > + * > > > + * The same thing as mentioned in the stencil case can happen in the > > depth > > > + * case as well if it thinks it writes depth but, thanks to the depth > > test > > > + * being GL_EQUAL, the write doesn't actually matter. A little extra > > work > > > + * up-front to try and disable depth and stencil writes can make a big > > > + * difference. > > > + * > > > + * Unfortunately, the way depth and stencil testing is specified, there > > are > > > + * many case where, regardless of depth/stencil writes being enabled, > > nothing > > > + * actually gets written due to some other bit of state being set. This > > > + * function attempts to "sanitize" the depth stencil state and disable > > writes > > > + * and sometimes even testing whenever possible. > > > + */ > > > +static void > > > +sanitize_ds_state(VkPipelineDepthStencilStateCreateInfo *state, > > > + bool *stencilWriteEnable, > > > + VkImageAspectFlags ds_aspects) > > > +{ > > > + *stencilWriteEnable = state->stencilTestEnable; > > > + > > > + /* If the depth test is disabled, we won't be writing anything. */ > > > + if (!state->depthTestEnable) > > > + state->depthWriteEnable = false; > > > + > > > + /* The Vulkan spec requires that if either depth or stencil is not > > present, > > > + * the pipeline is to act as if the test silently passes. > > > + */ > > > + if (!(ds_aspects & VK_IMAGE_ASPECT_DEPTH_BIT)) { > > > + state->depthWriteEnable = false; > > > + state->depthCompareOp = VK_COMPARE_OP_ALWAYS; > > > + } > > > + > > > + if (!(ds_aspects & VK_IMAGE_ASPECT_STENCIL_BIT)) { > > > + *stencilWriteEnable = false; > > > + state->front.compareOp = VK_COMPARE_OP_ALWAYS; > > > + state->back.compareOp = VK_COMPARE_OP_ALWAYS; > > > + } > > > + > > > + /* If the stencil test is enabled and always fails, then we will > > never get > > > + * to the depth test so we can just disable the depth test entirely. > > > + */ > > > + if (state->stencilTestEnable && > > > + state->front.compareOp == VK_COMPARE_OP_NEVER && > > > + state->back.compareOp == VK_COMPARE_OP_NEVER) { > > > + state->depthTestEnable = false; > > > + state->depthWriteEnable = false; > > > + } > > > + > > > + /* If depthCompareOp is EQUAL then the value we would be writing to > > the > > > + * depth buffer is the same as the value that's already there so > > there's no > > > + * point in writing it. > > > + */ > > > + if (state->depthCompareOp == VK_COMPARE_OP_EQUAL) > > > + state->depthWriteEnable = false; > > > + > > > + /* If the stencil ops are such that we don't actually ever modify the > > > + * stencil buffer, we should disable writes. > > > + */ > > > + if (!may_write_stencil_face(&state->front, state->depthCompareOp) && > > > + !may_write_stencil_face(&state->back, state->depthCompareOp)) > > > + *stencilWriteEnable = false; > > > + > > > + /* If the depth test always passes and we never write out depth, > > that's the > > > + * same as if the depth test is disabled entirely. > > > + */ > > > + if (state->depthCompareOp == VK_COMPARE_OP_ALWAYS && > > > + !state->depthWriteEnable) > > > + state->depthTestEnable = false; > > > + > > > + /* If the stencil test always passes and we never write out stencil, > > that's > > > + * the same as if the stencil test is disabled entirely. > > > + */ > > > + if (state->front.compareOp == VK_COMPARE_OP_ALWAYS && > > > + state->back.compareOp == VK_COMPARE_OP_ALWAYS && > > > + !*stencilWriteEnable) > > > + state->stencilTestEnable = false; > > > +} > > > + > > > static void > > > emit_ds_state(struct anv_pipeline *pipeline, > > > const VkPipelineDepthStencilStateCreateInfo *pCreateInfo, > > > @@ -663,12 +790,20 @@ emit_ds_state(struct anv_pipeline *pipeline, > > > return; > > > } > > > > > > + VkImageAspectFlags ds_aspects = 0; > > > + if (subpass->depth_stencil_attachment != VK_ATTACHMENT_UNUSED) { > > > + VkFormat depth_stencil_format = > > > + pass->attachments[subpass->depth_stencil_attachment].format; > > > + ds_aspects = vk_format_aspects(depth_stencil_format); > > > + } > > > + > > > VkPipelineDepthStencilStateCreateInfo info = *pCreateInfo; > > > + sanitize_ds_state(&info, &pipeline->writes_stencil, ds_aspects); > > > + pipeline->writes_depth = info.depthWriteEnable; > > > + pipeline->depth_test_enable = info.depthTestEnable; > > > > > > /* VkBool32 depthBoundsTestEnable; // optional (depth_bounds_test) */ > > > > > > - pipeline->writes_stencil = info.stencilTestEnable; > > > - > > > #if GEN_GEN <= 7 > > > struct GENX(DEPTH_STENCIL_STATE) depth_stencil = { > > > #else > > > @@ -690,38 +825,6 @@ emit_ds_state(struct anv_pipeline *pipeline, > > > .BackfaceStencilTestFunction = vk_to_gen_compare_op[info. > > back.compareOp], > > > }; > > > > > > - VkImageAspectFlags aspects = 0; > > > - if (subpass->depth_stencil_attachment != VK_ATTACHMENT_UNUSED) { > > > - VkFormat depth_stencil_format = > > > - pass->attachments[subpass->depth_stencil_attachment].format; > > > - aspects = vk_format_aspects(depth_stencil_format); > > > - } > > > - > > > - /* The Vulkan spec requires that if either depth or stencil is not > > present, > > > - * the pipeline is to act as if the test silently passes. > > > - */ > > > - if (!(aspects & VK_IMAGE_ASPECT_DEPTH_BIT)) { > > > - depth_stencil.DepthBufferWriteEnable = false; > > > - depth_stencil.DepthTestFunction = PREFILTEROPALWAYS; > > > - } > > > - > > > - if (!(aspects & VK_IMAGE_ASPECT_STENCIL_BIT)) { > > > - pipeline->writes_stencil = false; > > > - depth_stencil.StencilTestFunction = PREFILTEROPALWAYS; > > > - depth_stencil.BackfaceStencilTestFunction = PREFILTEROPALWAYS; > > > - } > > > - > > > - /* From the Broadwell PRM: > > > - * > > > - * "If Depth_Test_Enable = 1 AND Depth_Test_func = EQUAL, the > > > - * Depth_Write_Enable must be set to 0." > > > - */ > > > - if (info.depthTestEnable && info.depthCompareOp == > > VK_COMPARE_OP_EQUAL) > > > - depth_stencil.DepthBufferWriteEnable = false; > > > - > > > - pipeline->writes_depth = depth_stencil.DepthBufferWriteEnable; > > > - pipeline->depth_test_enable = depth_stencil.DepthTestEnable; > > > - > > > #if GEN_GEN <= 7 > > > GENX(DEPTH_STENCIL_STATE_pack)(NULL, depth_stencil_dw, > > &depth_stencil); > > > #else > > > -- > > > 2.5.0.400.gff86faf > > > > > > _______________________________________________ > > > mesa-dev mailing list > > > <a href="mailto:mesa-dev@lists.freedesktop.org">mesa-dev@lists.freedesktop.org</a> > > > <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> > > </div></div></blockquote></div> </div></div>