/te-ci L0

Greptile Summary

This PR updates the NCCL EP build in setup.py to respect the MAX_JOBS environment variable (and NVTE_BUILD_MAX_JOBS) by replacing the hardcoded os.cpu_count() or 8 with the shared get_max_jobs_for_parallel_build() utility already used by the CMake build path.

• get_max_jobs_for_parallel_build() returns 0 as a sentinel for "no limit", but the make invocation in setup.py unconditionally passes str(nproc) to -j, producing make -j 0 when no job limit is configured. The parallel build_ext.py call site correctly guards this with if max_jobs > 0; the same pattern is needed here.
• When a valid job count is provided via MAX_JOBS, the change works as intended and aligns the NCCL EP build with the rest of the TE build system.

Confidence Score: 4/5

Safe to merge if the make -j 0 edge case is addressed; builds that explicitly set MAX_JOBS work correctly today.

When no job-limit environment variable is set, get_max_jobs_for_parallel_build() returns 0 and the NCCL EP make invocation becomes make -j 0, whose behavior is undefined across GNU make versions. Builds with an explicit MAX_JOBS are unaffected, but the default (no-limit) path is broken in a way that depends on the host's make version.

setup.py — the make invocation needs the same if nproc > 0 guard that build_ext.py already uses for its CMake parallel argument.

Important Files Changed

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[build_nccl_ep_submodule] --> B[get_max_jobs_for_parallel_build]
    B --> C{env var set?}
    C -->|NVTE_BUILD_MAX_JOBS or MAX_JOBS| D[return N gt 0]
    C -->|none set| E[return 0]
    D --> F["make -j N (correct)"]
    E --> G["make -j 0 (undefined behavior)"]
    style G fill:#f66,color:#fff

_{Reviews (3): Last reviewed commit: "Merge branch 'main' into te_ep/fix_build" | Re-trigger Greptile}

/te-ci L0