[Bug]: NCCL timed out during inference

[enkiid]

Your current environment

Using:

• vllm 0.4.1
• nccl 2.18.1
• pytorch 2.2.1

🐛 Describe the bug

During inference I sometimes get this error:

(RayWorkerWrapper pid=2376582) [rank1]:[E ProcessGroupNCCL.cpp:523] [Rank 1] Watchdog caught collective operation timeout: WorkNCCL(SeqNum=50404, OpType=GATHER, NumelIn=8000, NumelOut=0, Timeout(ms)=600000) ran for 600327 milliseconds before timing out.

Havn't seen it in earlier versions of vllm, any thoughts?

[Ch3ngY1]

The same issue, which occurs randomly on my dataset.
vllm 0.4.1
torch 2.2.0+cu118

[DefTruth]

i have encountered the same issue, try --disable-custom-all-reduce and --enforce-eager is worked for me.

[changyuanzhangchina]

Please refer to #4430

1. --disable-custom-all-reduce = True
2. --enforce-eager = True (may be unnecessary)
3. update to the [Core] Ignore infeasible swap requests. #4557

This three can solve the watchdog problem for me
before this, nccl watchdog error happens several times per day,
and now, it works well

[yunfeng-scale]

we're seeing this on 0.4.2 as well with mixtral 8x22b. --disable-custom-all-reduce resolves the problem.

[yunfeng-scale]

can we again disable custom all reduce by default?

[syr-cn]

i have encountered the same issue, try --disable-custom-all-reduce and --enforce-eager is worked for me.

Works for me! thanks a lot!

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