From: Marek Olšák <marek.ol...@amd.com>
Heaven LDS usage for LS+HS is below. The masks are "outputs_written"
for LS and HS. Note that 32K is the maximum size.
Before:
heaven_x64: ls=1f1 tcs=1f1, lds=32K
heaven_x64: ls=31 tcs=31, lds=24K
heaven_x64: ls=71 tcs=71, lds=28K
After:
heaven_x64: ls=3f tcs=3f, lds=24K
heaven_x64: ls=7 tcs=7, lds=13K
heaven_x64: ls=f tcs=f, lds=17K
All other apps have a similar decrease in LDS usage, because
the "outputs_written" masks are similar. Also, most apps don't write
POSITION in these shader stages, so there is room for improvement.
(tight per-component input/output packing might help even more)
It's unknown whether this improves performance.
---
src/gallium/drivers/radeonsi/si_shader.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/src/gallium/drivers/radeonsi/si_shader.c
b/src/gallium/drivers/radeonsi/si_shader.c
index ddfaa3b..3a86c0b 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -129,32 +129,36 @@ unsigned si_shader_io_get_unique_index_patch(unsigned
semantic_name, unsigned in
/**
* Returns a unique index for a semantic name and index. The index must be
* less than 64, so that a 64-bit bitmask of used inputs or outputs can be
* calculated.
*/
unsigned si_shader_io_get_unique_index(unsigned semantic_name, unsigned index)
{
switch (semantic_name) {
case TGSI_SEMANTIC_POSITION:
return 0;
- case TGSI_SEMANTIC_PSIZE:
- return 1;
- case TGSI_SEMANTIC_CLIPDIST:
- assert(index <= 1);
- return 2 + index;
case TGSI_SEMANTIC_GENERIC:
+ /* Since some shader stages use the the highest used IO index
+ * to determine the size to allocate for inputs/outputs
+ * (in LDS, tess and GS rings). GENERIC should be placed right
+ * after POSITION to make that size as small as possible.
+ */
if (index < SI_MAX_IO_GENERIC)
- return 4 + index;
+ return 1 + index;
assert(!"invalid generic index");
return 0;
-
+ case TGSI_SEMANTIC_PSIZE:
+ return SI_MAX_IO_GENERIC + 1;
+ case TGSI_SEMANTIC_CLIPDIST:
+ assert(index <= 1);
+ return SI_MAX_IO_GENERIC + 2 + index;
case TGSI_SEMANTIC_FOG:
return SI_MAX_IO_GENERIC + 4;
case TGSI_SEMANTIC_LAYER:
return SI_MAX_IO_GENERIC + 5;
case TGSI_SEMANTIC_VIEWPORT_INDEX:
return SI_MAX_IO_GENERIC + 6;
case TGSI_SEMANTIC_PRIMID:
return SI_MAX_IO_GENERIC + 7;
case TGSI_SEMANTIC_COLOR: /* these alias */
case TGSI_SEMANTIC_BCOLOR:
--
2.7.4
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