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gfx950 channel tuning for ReduceScatter and AllGather (#1940)

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* add channel thresholds to override channel-count adjustments

[ROCm/rccl commit: 0f99fd84a3]
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isaki001 authored and GitHub committed 2025-10-14 09:50:44 -05:00
1 parent 433251272b
commit 6d151d4e21
7 files changed
+88 -4
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projects/rccl/src/enqueue.cc
+9 -1
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@@ -2015,6 +2015,8 @@ static ncclResult_t updateCollCostTable(
return ncclSuccess;
}
extern int64_t ncclParamMinNchannels();
static ncclResult_t topoGetAlgoInfo(
struct ncclComm* comm, struct ncclTaskColl* info, size_t nBytes,
float** collCostTable, ncclSimInfo_t* simInfo
@@ -2079,11 +2081,17 @@ static ncclResult_t topoGetAlgoInfo(
nc = comm->nvlsChannels;
} else {
rcclUpdateThreadThreshold(comm, nBytes, info, threadThreshold);
INFO(NCCL_INIT, "pre-adjustment threadThreshold:%i nBytes:%lu nc:%i", threadThreshold, nBytes, nc);
int minNChannels = ncclParamMinNchannels();
// Ring/Tree channel tuning
while (nBytes < nc * nt * threadThreshold) {
INFO(NCCL_INIT, "minNChannels:%i", minNChannels);
while (nBytes < nc * nt * threadThreshold && nc > minNChannels) {
if (nc >= 2) nc--;
else break;
}
INFO(NCCL_INIT, "post-adjustment based on threadThreshold:%i nBytes:%lu nc:%i", threadThreshold, nBytes, nc);
rcclOverrideChannels(comm, info->func, nBytes, nc);
}
#if defined(__HIP_PLATFORM_AMD__) || defined(__HIPCC__)
#else