[Mesa-dev] [PATCH] nv50/ir: do not perform global membar for shared memory

[Samuel Pitoiset]

Shared memory is local to CTA, thus we should only wait for
prior memory writes which are visible to other threads in
the same CTA, and not at global level. This should speedup
compute shaders which use shared memory.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
index b47fc49..621a468 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
@@ -3561,12 +3561,15 @@ Converter::handleInstruction(const struct tgsi_full_instruction *insn)
       geni->subOp = tgsi::opcodeToSubOp(tgsi.getOpcode());
       break;
    case TGSI_OPCODE_MEMBAR:
+   {
+      uint32_t level = tgsi.getSrc(0).getValueU32(0, info);
       geni = mkOp(OP_MEMBAR, TYPE_NONE, NULL);
       geni->fixed = 1;
-      if (tgsi.getSrc(0).getValueU32(0, info) & TGSI_MEMBAR_THREAD_GROUP)
+      if ((level & TGSI_MEMBAR_THREAD_GROUP) || level == TGSI_MEMBAR_SHARED)
          geni->subOp = NV50_IR_SUBOP_MEMBAR(M, CTA);
       else
          geni->subOp = NV50_IR_SUBOP_MEMBAR(M, GL);
+   }
       break;
    case TGSI_OPCODE_ATOMUADD:
    case TGSI_OPCODE_ATOMXCHG:
-- 
2.10.1