[Common] Update NCCL submodule to have the fix for MAX_SUPPORTED_TOKENS_PER_RANK

[phu0ngng]

Description

Update NCCL submodule to have the fix for MAX_SUPPORTED_TOKENS_PER_RANK

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Infra/Build change
• Code refactoring

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[greptile-apps]

Greptile Summary

This PR bumps the 3rdparty/nccl submodule to pick up the MAX_SUPPORTED_TOKENS_PER_RANK fix, and bundles two related improvements: reordering NCCL discovery in setup.py so ldconfig is consulted before well-known prefixes and the pip wheel (reducing ABI mismatch risk), and adding NVLink presence guards to all three EP test/bench scripts so they skip gracefully on hardware without NVLink P2P.

• Submodule bump (3rdparty/nccl): advances from 808d2433 to a6b5de08 to carry the upstream NCCL fix for MAX_SUPPORTED_TOKENS_PER_RANK.
• setup.py NCCL discovery reorder: ldconfig is now the first probe after NCCL_HOME, matching the dynamic loader's runtime resolution order and avoiding ABI mismatches when a pip wheel shadows a system NCCL.
• NVLink guard in shell scripts: all three EP scripts (run_test_ep.sh, run_ep_bench.sh, multi_process_launch_ep.sh) now call nvidia-smi nvlink --status and skip with exit 0 when NVLink is absent, preventing misleading failures on NVLink-less CI runners.

Confidence Score: 5/5

Safe to merge — the submodule bump carries a targeted upstream fix, the setup.py reorder aligns build-time and runtime NCCL resolution, and the NVLink guards are defensive skip-on-absence checks.

All changes are narrowly scoped: the submodule update is a single-commit upstream fix, the setup.py probe reordering preserves existing fallback paths and adds no new failure modes, and the NVLink shell guards only cause a test to skip gracefully rather than alter any test logic.

No files require special attention.

Important Files Changed

Filename	Overview
3rdparty/nccl	Submodule bump from 808d2433 to a6b5de08 to pick up the MAX_SUPPORTED_TOKENS_PER_RANK fix in NCCL.
setup.py	Reorders NCCL discovery: ldconfig is now consulted before well-known prefixes, and the pip wheel (nvidia-nccl-cu*) is moved to last resort; prevents ABI mismatches when the system loader resolves a different libnccl than the one used at build time.
tests/cpp_distributed/run_test_ep.sh	Adds an NVLink detection guard that skips the EP test when NVLink P2P is unavailable; uses consistent [[ ]] bash double-bracket style throughout.
examples/jax/ep/bench/run_ep_bench.sh	Adds the same NVLink detection guard as the test scripts; uses POSIX single-bracket for $? and -z checks, mixing styles with [[ ]] for pattern matching — inconsistent but functionally correct.
tests/jax/multi_process_launch_ep.sh	Adds NVLink detection guard matching the same pattern as the other scripts; mixed bracket styles (POSIX [ ] alongside [[ ]]) are consistent with the rest of this file.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[_discover_nccl_home] --> B{NCCL_HOME\nenv var set?}
    B -- yes --> C{nccl.h + libnccl\nexist at path?}
    C -- yes --> D[Return NCCL_HOME]
    C -- no --> E[Warning: NCCL_HOME\nset but invalid]
    B -- no --> F[ldconfig -p probe\nnew: checked first]
    E --> F
    F -- found --> G[Return ldconfig path]
    F -- not found --> H[Well-known prefix scan\n/opt/nvidia/nccl\n/usr/local/nccl\n/usr]
    H -- found --> I[Return prefix path]
    H -- not found --> J[pip wheel probe\nnvidia.nccl site-packages\nnew: last resort]
    J -- found --> K[Return pip wheel path]
    J -- not found --> L[RuntimeError:\nCould not locate NCCL]

    style F fill:#d4edda,stroke:#28a745
    style J fill:#fff3cd,stroke:#ffc107

Loading

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
    A[_discover_nccl_home] --> B{NCCL_HOME\nenv var set?}
    B -- yes --> C{nccl.h + libnccl\nexist at path?}
    C -- yes --> D[Return NCCL_HOME]
    C -- no --> E[Warning: NCCL_HOME\nset but invalid]
    B -- no --> F[ldconfig -p probe\nnew: checked first]
    E --> F
    F -- found --> G[Return ldconfig path]
    F -- not found --> H[Well-known prefix scan\n/opt/nvidia/nccl\n/usr/local/nccl\n/usr]
    H -- found --> I[Return prefix path]
    H -- not found --> J[pip wheel probe\nnvidia.nccl site-packages\nnew: last resort]
    J -- found --> K[Return pip wheel path]
    J -- not found --> L[RuntimeError:\nCould not locate NCCL]

    style F fill:#d4edda,stroke:#28a745
    style J fill:#fff3cd,stroke:#ffc107

Loading

_{Reviews (4): Last reviewed commit: "Merge branch 'main' into update_nccl" | Re-trigger Greptile}

[phu0ngng]

/te-ci L1

[phu0ngng]

/te-ci L1

[phu0ngng]

/te-ci L1

[phu0ngng]

/te-ci L1

[jberchtold-nvidia]

LGTM, thanks!