[BE]: Fix NVSHMEM builds, add missing 12.9 dependency and update to latest for 2.8RC by Skylion007 · Pull Request #157453 · pytorch/pytorch

Skylion007 · 2025-07-02T14:12:40Z

Fixed our bad builds of nvshmem, (we were not building or testing before) and also updates to the latest version. Newest versions has critical support for things that would actually make it useful, like bfloat16 and float16 support.

This is a proper fix for: #157411

pytorch-bot · 2025-07-02T14:12:43Z

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Skylion007 · 2025-07-02T14:43:05Z

Great Ubuntu is having an outage

atalman · 2025-07-02T15:00:41Z

cc @kwen2501 @ptrblck @nWEIdia @tinglvv @malfet

kwen2501

Thank you so much! LGTM!

kwen2501 · 2025-07-02T17:25:41Z

.ci/docker/common/install_cuda.sh

+  cp -a "libnvshmem/include/"* /usr/local/include/
+  cp -a "libnvshmem/lib/"*     /usr/local/lib/


Oh I was previously detecting NVSHMEM lib from python/site-packages/nvidia.
Maybe I would need to change how we set NVSHMEM_HOME based on this change?

It should be detected either way here? We do use NVSHMEM from the python package anyway at the end for non-static builds.

This is how we currently detect it for building:

pytorch/tools/setup_helpers/cmake.py

Lines 316 to 320 in d5d14ee

# Detect build dependencies from python lib path (in order to set *_HOME variables)

# NVSHMEM

nvshmem_home = py_lib_path + "/nvidia/nvshmem"

if os.path.exists(nvshmem_home):

build_options["NVSHMEM_HOME"] = nvshmem_home

And there is a gate here that stops building torch with NVSHMEM if NVSHMEM_HOME is not set:

pytorch/caffe2/CMakeLists.txt

Lines 998 to 1002 in 0105cd8

if(NOT DEFINED NVSHMEM_HOME)

message(WARNING "NVSHMEM_HOME not found. Please run `pip install nvidia-nvshmem-<version>`, or set NVSHMEM_HOME to its location.")

# Disable nvshmem if NVSHMEM_HOME is not found

set(USE_NVSHMEM FALSE)

endif()

I see two solutions:
(1) We add export NVSHMEM_HOME=/usr/local here, but it looks a bit weird;
(2) We add a findNVSHMEM.cmake as a single place to detect the library and set NVSHMEM_HOME there.

What do you think?

I'd say a findNVSHMEM.cmake

The pip version is fine too obviously, but it didn't seem to work for you other build?

So libnvshmem comes with libnvshmem/lib/cmake/nvshmem/NVSHMEMConfig.cmake, but it doesn't set the NVSHMEM home.

@kwen2501 This more complicated as our current CMake is broken when we build with NVSHMEM because it tries to build for unsupported architectures.

@kwen2501 Also libtorch will be missing it now, right?

Correct. So we'd need to find a way to work for both. (pip install or system install)

@kwen2501 Proper way is just do CMake. It will work pip install thanks the to the rpath changes we made.

Thanks. I added CMake search here: #157513.
Do you mind taking a look? Thank you!

atalman · 2025-07-03T18:00:26Z

@pytorchmergebot merge

pytorchmergebot · 2025-07-03T18:02:15Z

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Skylion007 · 2025-07-03T19:44:43Z

@atalman This is needed first as it's not actually able to find the installed NVSHMEM currently: #157513

…ation" Previously we only search for NVSHMEM from pip install location. This PR adds search in system locations deemed default by CMake. Related: #157453 untars NVSHMEM into `/usr/local` on our CI machines. cc H-Huang awgu wanchaol fegin fduwjj wz337 wconstab d4l3k Skylion007 [ghstack-poisoned]

Previously we only search for NVSHMEM from pip install location. This PR adds search in system locations deemed default by CMake. Related: #157453 untars NVSHMEM into `/usr/local` on our CI machines. cc H-Huang awgu wanchaol fegin fduwjj wz337 wconstab d4l3k Skylion007 [ghstack-poisoned]

Previously we only search for NVSHMEM from pip install location. This PR adds search in system locations deemed default by CMake. Related: #157453 untars NVSHMEM into `/usr/local` on our CI machines. Pull Request resolved: #157513 Approved by: https://github.com/atalman, https://github.com/Skylion007

…ation" Previously we only search for NVSHMEM from pip install location. This PR adds search in system locations deemed default by CMake. Related: #157453 untars NVSHMEM into `/usr/local` on our CI machines. cc H-Huang awgu wanchaol fegin fduwjj wz337 wconstab d4l3k Skylion007 [ghstack-poisoned]

Previously we only search for NVSHMEM from pip install location. This PR adds search in system locations deemed default by CMake. Related: #157453 untars NVSHMEM into `/usr/local` on our CI machines. cc H-Huang awgu wanchaol fegin fduwjj wz337 wconstab d4l3k Skylion007 [ghstack-poisoned]

Previously we only search for NVSHMEM from pip install location. This PR adds search in system locations deemed default by CMake. Related: #157453 untars NVSHMEM into `/usr/local` on our CI machines. Pull Request resolved: #157513 Approved by: https://github.com/atalman, https://github.com/Skylion007 (cherry picked from commit 99c1a6b)

kwen2501 · 2025-07-08T05:56:21Z

@pytorchbot cherry-pick --onto release/2.8 -c critical

…atest for 2.8RC (#157453) Fixed our bad builds of nvshmem, (we were not building or testing before) and also updates to the latest version. Newest versions has critical support for things that would actually make it useful, like bfloat16 and float16 support. This is a proper fix for: #157411 Pull Request resolved: #157453 Approved by: https://github.com/kwen2501, https://github.com/atalman (cherry picked from commit a6fab82)

pytorchbot · 2025-07-08T06:01:10Z

Cherry picking #157453

The cherry pick PR is at #157774 and it is recommended to link a critical cherry pick PR with an issue. The following tracker issues are updated:

[v.2.8.0] Release Tracker #156745 (comment)

Details for Dev Infra team

Raised by workflow job

Skylion007 requested review from atalman, eqy and nWEIdia July 2, 2025 14:12

Skylion007 requested review from a team and jeffdaily as code owners July 2, 2025 14:12

pytorch-bot bot added the topic: not user facing topic category label Jul 2, 2025

pytorchbot added the open source label Jul 2, 2025

Skylion007 force-pushed the skylion007/update-nvshmem-3-3-9 branch from 8119930 to 99dabab Compare July 2, 2025 14:17

Skylion007 changed the title ~~[BE]: Fix NVSHMEM builds and update to latest~~ [BE]: Fix NVSHMEM builds, add missing 12.9 dependency and update to latest Jul 2, 2025

Skylion007 force-pushed the skylion007/update-nvshmem-3-3-9 branch 3 times, most recently from c76ed71 to 1b12f69 Compare July 2, 2025 14:32

Skylion007 requested review from malfet and tinglvv July 2, 2025 14:39

Skylion007 added the better-engineering Relatively self-contained tasks for better engineering contributors label Jul 2, 2025

Skylion007 force-pushed the skylion007/update-nvshmem-3-3-9 branch from 1b12f69 to f8899ce Compare July 2, 2025 14:46

Skylion007 changed the title ~~[BE]: Fix NVSHMEM builds, add missing 12.9 dependency and update to latest~~ [BE]: Fix NVSHMEM builds, add missing 12.9 dependency and update to latest for 2.8RC Jul 2, 2025

Skylion007 added this to the 2.8.0 milestone Jul 2, 2025

Skylion007 force-pushed the skylion007/update-nvshmem-3-3-9 branch from f8899ce to c84bbb0 Compare July 2, 2025 14:56

atalman added the ciflow/binaries Trigger all binary build and upload jobs on the PR label Jul 2, 2025

[BE]: Fix NVSHMEM builds and update to latest

c2d6d7b

Skylion007 force-pushed the skylion007/update-nvshmem-3-3-9 branch from c84bbb0 to c2d6d7b Compare July 2, 2025 16:30

kwen2501 approved these changes Jul 2, 2025

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kwen2501 reviewed Jul 2, 2025

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This was referenced Jul 2, 2025

[SymmMem] Install NVSHMEM wheel in CI docker #157411

Closed

[SymmMem] Find NVSHMEM from system installation #157513

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atalman approved these changes Jul 2, 2025

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pytorchmergebot closed this in a6fab82 Jul 3, 2025

pytorchmergebot removed the merging label Jul 3, 2025

pytorchbot mentioned this pull request Jul 8, 2025

[SymmMem] Find NVSHMEM from system installation #157755

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pytorchbot mentioned this pull request Jul 8, 2025

[v.2.8.0] Release Tracker #156745

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atalman removed this from the 2.8.0 milestone Jul 11, 2025

		cp -a "libnvshmem/include/"* /usr/local/include/
		cp -a "libnvshmem/lib/"* /usr/local/lib/

	# Detect build dependencies from python lib path (in order to set *_HOME variables)
	# NVSHMEM
	nvshmem_home = py_lib_path + "/nvidia/nvshmem"
	if os.path.exists(nvshmem_home):
	build_options["NVSHMEM_HOME"] = nvshmem_home

	if(NOT DEFINED NVSHMEM_HOME)
	message(WARNING "NVSHMEM_HOME not found. Please run `pip install nvidia-nvshmem-<version>`, or set NVSHMEM_HOME to its location.")
	# Disable nvshmem if NVSHMEM_HOME is not found
	set(USE_NVSHMEM FALSE)
	endif()

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Cherry picking #157453

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