Matt Sinclair has submitted this change. (
https://gem5-review.googlesource.com/c/public/gem5/+/38696 )
Change subject: gpu-compute: Fix FLAT insts decrementing lgkm count early
..
gpu-compute: Fix FLAT insts decrementing lgkm count early
FLAT instructions used to decrement lgkm count on execute, while the
GCN3 ISA specifies that lgkm count should be decremented on data being
returned or data being written.
This patch changes it so that lgkm is decremented after initiateAcc (for
stores) and after completeAcc (for loads) to better reflect the ISA
definition.
This fixes a bug where waitcnts would be satisfied even though the
memory access wasn't completed, which lead to instructions using the
wrong data.
Change-Id: I596cb031af9cda8d47a1b5e146e4a4ffd793d36c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/38696
Reviewed-by: Matt Sinclair
Reviewed-by: Matthew Poremba
Maintainer: Matt Sinclair
Tested-by: kokoro
---
M src/gpu-compute/global_memory_pipeline.cc
M src/gpu-compute/gpu_dyn_inst.cc
2 files changed, 7 insertions(+), 1 deletion(-)
Approvals:
Matthew Poremba: Looks good to me, approved
Matt Sinclair: Looks good to me, but someone else must approve; Looks
good to me, approved
kokoro: Regressions pass
diff --git a/src/gpu-compute/global_memory_pipeline.cc
b/src/gpu-compute/global_memory_pipeline.cc
index bcd93f8..a2b24e4 100644
--- a/src/gpu-compute/global_memory_pipeline.cc
+++ b/src/gpu-compute/global_memory_pipeline.cc
@@ -130,6 +130,9 @@
DPRINTF(GPUMem, "CU%d: WF[%d][%d]: Completing global mem
instr %s\n",
m->cu_id, m->simdId, m->wfSlotId, m->disassemble());
m->completeAcc(m);
+if (m->isFlat() && m->isLoad()) {
+w->decLGKMInstsIssued();
+}
w->decVMemInstsIssued();
if (m->isLoad() || m->isAtomicRet()) {
@@ -193,6 +196,10 @@
mp->disassemble(), mp->seqNum());
mp->initiateAcc(mp);
+if (mp->isFlat() && mp->isStore()) {
+mp->wavefront()->decLGKMInstsIssued();
+}
+
if (mp->isStore() && mp->isGlobalSeg()) {
mp->wavefront()->decExpInstsIssued();
}
diff --git a/src/gpu-compute/gpu_dyn_inst.cc
b/src/gpu-compute/gpu_dyn_inst.cc
index 03ed689..38e4ecf 100644
--- a/src/gpu-compute/gpu_dyn_inst.cc
+++ b/src/gpu-compute/gpu_dyn_inst.cc
@@ -819,7 +819,6 @@
if (executedAs() == Enums::SC_GLOBAL) {
// no transormation for global segment
wavefront()->execUnitId = wavefront()->flatGmUnitId;
-wavefront()->decLGKMInstsIssued();
if (isLoad()) {
wavefront()->rdLmReqsInPipe--;
} else if (isStore()) {
--
To view, visit https://gem5-review.googlesource.com/c/public/gem5/+/38696
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Gerrit-Project: public/gem5
Gerrit-Branch: develop
Gerrit-Change-Id: I596cb031af9cda8d47a1b5e146e4a4ffd793d36c
Gerrit-Change-Number: 38696
Gerrit-PatchSet: 4
Gerrit-Owner: Kyle Roarty
Gerrit-Reviewer: Alexandru Duțu
Gerrit-Reviewer: Matt Sinclair
Gerrit-Reviewer: Matthew Poremba
Gerrit-Reviewer: kokoro
Gerrit-MessageType: merged
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