[Misc] Compute query_start_loc on CPU

[zhengy001]

FILL IN THE PR DESCRIPTION HERE

Avoid creating intermediate tensor query_lens_tensor and compute query_start_loc on CPU and allow h2d async.

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[zhengy001]

Can someone explain what does buildkite/fastcheck/pr/docker-build-image test do?

[DarkLight1337]

Can someone explain what does buildkite/fastcheck/pr/docker-build-image test do?

Sorry for the late reply, it builds the docker image which is used to run all of the tests. I have retried this step just now.

[mergify[bot]]

This pull request has merge conflicts that must be resolved before it can be merged. @zhengy001 please rebase it. https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[Isotr0py]

@zhengy001 Can you run a benchmark for this PR? LGTM once the performance is determined to be still reasonable. (I don't have idle device to run with FA2 backend right now)

You can run benchmark with following commands:

python3 benchmark_throughput.py \
    --model meta-llama/Meta-Llama-3.1-8B-Instruct \
    --backend vllm \
    --input-len 292 \
    --output-len 579 \
    --num-prompts 1000

[zhengy001]

@zhengy001 Can you run a benchmark for this PR? LGTM once the performance is determined to be still reasonable. (I don't have idle device to run with FA2 backend right now)

You can run benchmark with following commands:

python3 benchmark_throughput.py \
    --model meta-llama/Meta-Llama-3.1-8B-Instruct \
    --backend vllm \
    --input-len 292 \
    --output-len 579 \
    --num-prompts 1000

I use Llama2-7B

Before: Throughput: 7.48 requests/s, 6512.49 total tokens/s, 4329.20 output tokens/s

After: Throughput: 7.48 requests/s, 6511.69 total tokens/s, 4328.67 output tokens/s

[zhengy001]

LGTM! The benchmark result looks reasonable!

Thanks, @Isotr0py, do you know the failed buildkite/fastcheck/pr/tpu-test error?

Seems unrelated, do you know how to retry CI?

[Isotr0py]

You can sync this PR branch with the main branch to re-run the CI from new commit.

[zhengy001]

You can sync this PR branch with the main branch to re-run the CI from new commit.

Okay, thanks.