[Bugfix] Avoid to warmup when world size is 1

[kerthcet]

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xref: #4587

@youkaichao I have no env to test with the vGPU+vLLM, but at least we can avoid to warmup when the worldsize = 1, do you agree?

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[youkaichao]

I agree with the idea, but why this PR touches so many lines?

You just need to avoid the warmup if world size > 1.

[kerthcet]

Ok, got your idea about avoid warmup once worldsize is 1, what I did here is slightly different. Will modify as you suggested.

[kerthcet]

Done

[youkaichao]

can you revert the format change? let's keep the pr clean on what is changed.

[kerthcet]

can you revert the format change? let's keep the pr clean on what is changed.

Make sense to me, I used to make them separate commits. Anyway, reverted.

[youkaichao]

Thanks for addressing my comments! It can be merged once it passed all the tests.

[kerthcet]

Thanks for the quick reply.

[kerthcet]

It's weird, the test buildkite/ci/pr pending for several hours, still not finished.

[kerthcet]

Seems we totally removed the warmup in #5293, can I know the reason here? @youkaichao

[youkaichao]

oh, I just happen to remove the warmup because I don't want the warmup for world/tp/pp group. sorry for overwriting your PR!

[kerthcet]

Make sense, seems we can close now.