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Fix using dO stride for O, which can cause memory error in bwd

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This commit is contained in:
Tri Dao 2023-07-20 17:39:00 -07:00
parent 2dd87d0609
commit 9ee0ff1d9b
1 changed files with 4 additions and 4 deletions
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8
csrc/flash_attn/src/flash_bwd_kernel.h
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@ -141,7 +141,7 @@ inline __device__ void compute_dot_do_o(const Params &params) {
make_stride(params.do_row_stride, _1{}));
Tensor gO = make_tensor(make_gmem_ptr(reinterpret_cast<Element *>(params.o_ptr) + row_offset_o),
Shape<Int<kBlockM>, Int<kHeadDim>>{},
make_stride(params.do_row_stride, _1{}));
make_stride(params.o_row_stride, _1{}));
Tensor gdQaccum = make_tensor(make_gmem_ptr(reinterpret_cast<ElementAccum *>(params.dq_accum_ptr) + row_offset_dq_accum),
Shape<Int<kBlockM>, Int<kHeadDim>>{}, Stride<Int<kHeadDim>, _1>{});
Tensor dP_sum = make_tensor(make_gmem_ptr(reinterpret_cast<ElementAccum *>(params.dsoftmax_sum) + row_offset_dpsum),
@ -474,7 +474,7 @@ inline __device__ void compute_dq_dk_dv_1colblock(const Params &params, const in
make_stride(params.do_row_stride, _1{}));
Tensor gO = make_tensor(make_gmem_ptr(reinterpret_cast<Element *>(params.o_ptr) + row_offset_o),
Shape<Int<kBlockM>, Int<kHeadDim>>{},
make_stride(params.do_row_stride, _1{}));
make_stride(params.o_row_stride, _1{}));
Tensor gdQ = make_tensor(make_gmem_ptr(reinterpret_cast<Element *>(params.dq_ptr) + row_offset_dq),
Shape<Int<kBlockM>, Int<kHeadDim>>{},
make_stride(params.dq_row_stride, _1{}));
@ -1098,7 +1098,7 @@ inline __device__ void compute_dq_dk_dv_1rowblock(const Params &params, const in
const index_t row_offset_do = binfo.q_offset(params.do_batch_stride, params.do_row_stride, bidb)
+ m_block * kBlockM * params.do_row_stride + bidh * params.do_head_stride;
const index_t row_offset_o = binfo.q_offset(params.o_batch_stride, params.o_row_stride, bidb)
+ m_block * kBlockM * params.do_row_stride + bidh * params.o_head_stride;
+ m_block * kBlockM * params.o_row_stride + bidh * params.o_head_stride;
// We'll advance gdKaccum and gdVaccum before the first write.
const index_t row_offset_dkv_accum = ((bidb * params.h_k + (bidh / params.h_h_k_ratio)) * params.seqlen_k_rounded
+ n_block_max * kBlockN) * params.d_rounded;
@ -1119,7 +1119,7 @@ inline __device__ void compute_dq_dk_dv_1rowblock(const Params &params, const in
make_stride(params.do_row_stride, _1{}));
Tensor gO = make_tensor(make_gmem_ptr(reinterpret_cast<Element *>(params.o_ptr) + row_offset_o),
Shape<Int<kBlockM>, Int<kHeadDim>>{},
make_stride(params.do_row_stride, _1{}));
make_stride(params.o_row_stride, _1{}));
Tensor gdKaccum = make_tensor(make_gmem_ptr(reinterpret_cast<ElementAccum *>(params.dk_accum_ptr) + row_offset_dkv_accum),
Shape<Int<kBlockN>, Int<kHeadDim>>{},
Stride<Int<kHeadDim>, _1>{});