[Openmp-commits] [openmp] [OpenMP][libomptarget] Use two SDMA engines (PR #73633)

[Jan Patrick Lehr via Openmp-commits]

https://github.com/jplehr created https://github.com/llvm/llvm-project/pull/73633

Limit the use to two SDMA engines to resolve issues with certain cards.

>From 78e5e0c81e5d7a1390829e0d90d0ec23b0c99b1e Mon Sep 17 00:00:00 2001
From: JP Lehr <JanPatrick.Lehr at amd.com>
Date: Tue, 28 Nov 2023 05:32:42 -0500
Subject: [PATCH] [OpenMP][libomptarget] Use two SDMA engines

Limit the use to two SDMA engines to resolve issues with certain cards.
---
 openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp b/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp
index 208cce90d8e9277..b3eed60d2879d48 100644
--- a/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp
+++ b/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp
@@ -161,8 +161,8 @@ Error asyncMemCopy(bool UseMultipleSdmaEngines, void *Dst, hsa_agent_t DstAgent,
       Dst, DstAgent, Src, SrcAgent, Size, NumDepSignals, DepSignals,
       CompletionSignal, (hsa_amd_sdma_engine_id_t)LocalSdmaEngine,
       /*force_copy_on_sdma=*/true);
-  // Increment to use one of three SDMA engines: 0x1, 0x2, 0x4
-  LocalSdmaEngine = (LocalSdmaEngine << 1) % 7;
+  // Increment to use one of two SDMA engines: 0x1, 0x2
+  LocalSdmaEngine = (LocalSdmaEngine << 1) % 3;
   SdmaEngine.store(LocalSdmaEngine, std::memory_order_relaxed);
 
   return Plugin::check(S, "Error in hsa_amd_memory_async_copy_on_engine: %s");