candle-flash-attn-v1/kernels/fmha_kernel.h

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#pragma once

#include "philox.cuh"

#include "fmha.h"
#include "fmha/utils.h"
#include "fmha/smem_tile.h"
#include "fmha/gmem_tile.h"
#include "fmha/mask.h"
#include "fmha/softmax.h"

namespace fmha {

////////////////////////////////////////////////////////////////////////////////////////////////////

template<int THREADS_PER_CTA>
struct BlockInfoPadded {

    template<typename Params>
    __device__ BlockInfoPadded(const Params &params,
                               const int bidb,
                               const int bidh,
                               const int tidx)
        : bidb(bidb), bidh(bidh), h(params.h) {

        // The block index.
        sum_s_k = params.cu_seqlens_k[bidb];
        actual_seqlen_k = params.cu_seqlens_k[bidb + 1] - sum_s_k;
        sum_s_q = params.cu_seqlens_q[bidb];
        actual_seqlen_q = params.cu_seqlens_q[bidb + 1] - sum_s_q;

        tidx_global = (bidb * params.h + bidh) * THREADS_PER_CTA + tidx;
    }

    __device__ bool stop_early(const int start_col = 0) const {
        return actual_seqlen_k <= start_col;
    }

    int actual_seqlen_q;
    int actual_seqlen_k;
    int sum_s_q;
    int sum_s_k;
    int bidh;
    int bidb;
    int tidx_global;
    int h;
};

////////////////////////////////////////////////////////////////////////////////////////////////////

}  // namespace fmha