[ROCm][Hardware][AMD] Enable group query attention for triton FA

[hongxiayang]

Enable group-query-attention for Triton flash attention

cc Vinayak Gokhale @vgokhale , @Alexei-V-Ivanov-AMD

FIX #xxxx (link existing issues this PR will resolve)

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[WoosukKwon]

@hongxiayang LGTM! thanks for submitting the PR! I've checked that the PR works well on Llama-3 8B.

BTW, does this fully utilize the benefit of GQA? IIUC, each query head redundantly reads the shared KV cache, missing the opportunity to save HBM bandwidth. If this is correct, do you have a plan to add this optimization to the Triton kernel?

[hongxiayang]

@hongxiayang LGTM! thanks for submitting the PR! I've checked that the PR works well on Llama-3 8B.

@WoosukKwon Thanks for the quick merge and verifying it using llama3-8b. I verified on llama2-70b and llama3-70b as well.

BTW, does this fully utilize the benefit of GQA? IIUC, each query head redundantly reads the shared KV cache, missing the opportunity to save HBM bandwidth. If this is correct, do you have a plan to add this optimization to the Triton kernel?

We will take a look and further work is in the planning. Would you mind sharing the location where the redundantly reads happening today?