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Intra-node shared memory (SHM) optimizations for CPU primitives #458

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Intra-node shared memory (SHM) optimizations for CPU primitives #458

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1738e8e
add shm allreduce
gaopengff Jul 11, 2025
76d1114
add bf16 and half support
gaopengff Jul 16, 2025
2d152a3
remove bf16 support
gaopengff Jul 18, 2025
8c29eeb
add bf16 support
gaopengff Jul 22, 2025
554d317
use reduce function to do reduce job
gaopengff Jul 24, 2025
0fdde35
refine format
gaopengff Jul 24, 2025
be7da7c
fix accuracy issue
gaopengff Aug 11, 2025
5b698dc
move intro-node check to allreduce()
gaopengff Aug 18, 2025
3564e95
remove debug code
gaopengff Aug 20, 2025
3ac8065
use local_rank to check intra-node condition
gaopengff Aug 25, 2025
8d3ae22
add support for multi-thread and code for local reduction
gaopengff Aug 29, 2025
2985c3e
move intra-node check to createAndConnectAllPairs
gaopengff Sep 1, 2025
704d35d
update to main
gaopengff Sep 1, 2025
9ae2842
add check for gpu input and fix format issue
gaopengff Sep 3, 2025
1b7660a
fix format issue
gaopengff Sep 3, 2025
ab9c63b
fix timeout ut
gaopengff Sep 5, 2025
9f726e9
add fininalize method and fix ut
gaopengff Sep 12, 2025
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2 changes: 2 additions & 0 deletions gloo/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@ list(APPEND GLOO_SRCS
"${CMAKE_CURRENT_SOURCE_DIR}/allgatherv.cc"
"${CMAKE_CURRENT_SOURCE_DIR}/allreduce.cc"
"${CMAKE_CURRENT_SOURCE_DIR}/allreduce_local.cc"
"${CMAKE_CURRENT_SOURCE_DIR}/allreduce_shm.cc"
"${CMAKE_CURRENT_SOURCE_DIR}/alltoall.cc"
"${CMAKE_CURRENT_SOURCE_DIR}/alltoallv.cc"
"${CMAKE_CURRENT_SOURCE_DIR}/barrier.cc"
Expand All @@ -34,6 +35,7 @@ list(APPEND GLOO_HDRS
"${CMAKE_CURRENT_SOURCE_DIR}/allreduce_local.h"
"${CMAKE_CURRENT_SOURCE_DIR}/allreduce_ring.h"
"${CMAKE_CURRENT_SOURCE_DIR}/allreduce_ring_chunked.h"
"${CMAKE_CURRENT_SOURCE_DIR}/allreduce_shm.h"
"${CMAKE_CURRENT_SOURCE_DIR}/alltoall.h"
"${CMAKE_CURRENT_SOURCE_DIR}/alltoallv.h"
"${CMAKE_CURRENT_SOURCE_DIR}/barrier.h"
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13 changes: 12 additions & 1 deletion gloo/allreduce.cc
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Expand Up @@ -15,6 +15,7 @@
#include "gloo/common/logging.h"
#include "gloo/math.h"
#include "gloo/types.h"
#include "gloo/allreduce_shm.h"

namespace gloo {

Expand Down Expand Up @@ -131,14 +132,23 @@ void allreduce(const detail::AllreduceOptionsImpl& opts) {
return;
}

switch (opts.algorithm) {
auto algorithm = opts.algorithm;
if (is_intra_node(opts)) {
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@d4l3k d4l3k Aug 29, 2025

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Doing a broadcast prior to every single allreduce seems pretty expensive -- can we move this logic to the TCP init in createAndConnectAllPairs? We have enough information there I believe to compute the topology since we have all the hostnames.

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@d4l3k d4l3k Aug 29, 2025

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The other option would be to inspect the pairs that are participating and check if they all share the same IP

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@gaopengff gaopengff Sep 1, 2025 •
edited
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Thanks for you advice. I have moved intra-node checking to createAndConnectAllPairs and it would use hostnames for checking. Could you help review? Thanks.

algorithm = detail::AllreduceOptionsImpl::SHM;
}


switch (algorithm) {
case detail::AllreduceOptionsImpl::UNSPECIFIED:
case detail::AllreduceOptionsImpl::RING:
ring(opts, reduceInputs, broadcastOutputs);
break;
case detail::AllreduceOptionsImpl::BCUBE:
bcube(opts, reduceInputs, broadcastOutputs);
break;
case detail::AllreduceOptionsImpl::SHM:
shm(opts);
break;
default:
GLOO_ENFORCE(false, "Algorithm not handled.");
}
Expand All @@ -153,6 +163,7 @@ void ring(
const auto slot = Slot::build(kAllreduceSlotPrefix, opts.tag);
const size_t totalBytes = opts.elements * opts.elementSize;


// Note: context->size > 1
const auto recvRank = (context->size + context->rank + 1) % context->size;
const auto sendRank = (context->size + context->rank - 1) % context->size;
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1 change: 1 addition & 0 deletions gloo/allreduce.h
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Expand Up @@ -39,6 +39,7 @@ struct AllreduceOptionsImpl {
UNSPECIFIED = 0,
RING = 1,
BCUBE = 2,
SHM = 3,
};

explicit AllreduceOptionsImpl(const std::shared_ptr<Context>& context)
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