This seemed to help Dota 2 by a percent or two.
---
src/intel/vulkan/genX_pipeline.c | 133 +++++++++++++++++++++++++++++----------
1 file changed, 99 insertions(+), 34 deletions(-)
diff --git a/src/intel/vulkan/genX_pipeline.c b/src/intel/vulkan/genX_pipeline.c
index f6940d2..1961874 100644
--- a/src/intel/vulkan/genX_pipeline.c
+++ b/src/intel/vulkan/genX_pipeline.c
@@ -634,6 +634,95 @@ 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)
+{
+ return (face->compareOp != VK_COMPARE_OP_ALWAYS &&
+ face->failOp != VK_STENCIL_OP_KEEP) ||
+ (face->compareOp != VK_COMPARE_OP_NEVER &&
+ ((depthCompareOp != VK_COMPARE_OP_NEVER &&
+ face->passOp != VK_STENCIL_OP_KEEP) ||
+ (depthCompareOp != VK_COMPARE_OP_ALWAYS &&
+ face->depthFailOp != VK_STENCIL_OP_KEEP)));
+}
+
+/* Intel hardware is fairly sensitive to whether or not depth/stencil writes
+ * are enabled. In the presence of discards, disabling writes means that the
+ * depth/stencil testing can get moved earlier in the pipeline which allows it
+ * to avoid executing the fragment shader of the depth or stencil test fails.
+ *
+ * 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,
@@ -656,12 +745,20 @@ 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
@@ -683,38 +780,6 @@ 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)) {
- depth_stencil.StencilBufferWriteEnable = 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
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