flash-attention/csrc/flash_attn_ck/flash_api.cpp
rocking d8f104e97a
Support AMD ROCm on FlashAttention 2 (#1010)
* Support ck in fmha

* Add ck submodule

* Do not return lse if return_softmax == false

* Use receipt to speed up ck compile time

* Integrate new version of ck_tile

* Support dropout for mha_fwd()

* Add dropout to mha_varlen_fwd()

* Update ck to develop

* Extract padding function for dropout randval

* Extract randval transformation function

* Sync the code structure and coding style with FA

* Remove this line, c++ api will handle this.
Sync with test_flash_attn.py

* fix compile error

* Add mha_bwd

* Generate dropout seed and offset from user generator

* update CK

* Add mha_varlen_bwd

* Use same python as build flash-attn to generate ck kernel

* Fix bug of group mode fwd about returning softmax lse

* larger the test tollerance

* Add test_flash_attn_output() and test_flash_attn_varlen_output()

* Always fill softmax_lse

* Remove duplicate benchmark script, since we already implement mha_bwd

* Refine get value from tuple

* Use default parameter for stream_config

* unblock all platform

* Add comment

* refine the test code

* Refine naming

* Add unpack to namespace

* Do not hardcode the warp size 64

* Add more targets

* Add README

* Optimize mha_fwd if seqlen_q == 1

* Support get_wheel_url for rocm

* Detect rocm environment by pytorch's IS_HIP_EXTENSION

* update to lastest ck

* Add necessary compile flag

* Sync the api with upstream FA

---------

Co-authored-by: carlushuang <carlus.huang@amd.com>
Co-authored-by: Yichen Yan <wenji.yyc@alibaba-inc.com>
Co-authored-by: Po Yen Chen <PoYen.Chen@amd.com>
Co-authored-by: Yichen Yan <oraluben@outlook.com>
2024-07-22 21:34:37 -07:00

100 lines
5.7 KiB
C++

/******************************************************************************
* Copyright (c) 2024, Tri Dao.
******************************************************************************/
#include "flash_common.hpp"
std::vector<at::Tensor>
mha_fwd(at::Tensor &q,
const at::Tensor &k,
const at::Tensor &v,
c10::optional<at::Tensor> &out_,
c10::optional<at::Tensor> &alibi_slopes_,
const float p_dropout,
const float softmax_scale,
bool is_causal,
int window_size_left,
int window_size_right,
const float softcap,
const bool return_softmax,
c10::optional<at::Generator> gen_);
std::vector<at::Tensor>
mha_varlen_fwd(at::Tensor &q, // total_q x num_heads x head_size, total_q := \sum_{i=0}^{b} s_i
const at::Tensor &k, // total_k x num_heads_k x head_size, total_k := \sum_{i=0}^{b} s_i or num_blocks x page_block_size x num_heads_k x head_size if there's a block_table.
const at::Tensor &v, // total_k x num_heads_k x head_size, total_k := \sum_{i=0}^{b} s_i or num_blocks x page_block_size x num_heads_k x head_size if there's a block_table.
c10::optional<at::Tensor> &out_, // total_q x num_heads x head_size, total_k := \sum_{i=0}^{b} s_i
const at::Tensor &cu_seqlens_q, // b+1
const at::Tensor &cu_seqlens_k, // b+1
c10::optional<at::Tensor> &seqused_k, // b. If given, only this many elements of each batch element's keys are used.
c10::optional<const at::Tensor> &leftpad_k_, // batch_size
c10::optional<at::Tensor> &block_table_, // batch_size x max_num_blocks_per_seq
c10::optional<at::Tensor> &alibi_slopes_, // num_heads or b x num_heads
int max_seqlen_q,
const int max_seqlen_k,
const float p_dropout,
const float softmax_scale,
const bool zero_tensors,
bool is_causal,
int window_size_left,
int window_size_right,
const float softcap,
const bool return_softmax,
c10::optional<at::Generator> gen_);
std::vector<at::Tensor>
mha_bwd(const at::Tensor &dout, // batch_size x seqlen_q x num_heads, x head_size_og
const at::Tensor &q, // batch_size x seqlen_q x num_heads x head_size
const at::Tensor &k, // batch_size x seqlen_k x num_heads_k x head_size
const at::Tensor &v, // batch_size x seqlen_k x num_heads_k x head_size
const at::Tensor &out, // batch_size x seqlen_q x num_heads x head_size
const at::Tensor &softmax_lse, // b x h x seqlen_q
c10::optional<at::Tensor> &dq_, // batch_size x seqlen_q x num_heads x head_size
c10::optional<at::Tensor> &dk_, // batch_size x seqlen_k x num_heads_k x head_size
c10::optional<at::Tensor> &dv_, // batch_size x seqlen_k x num_heads_k x head_size
c10::optional<at::Tensor> &alibi_slopes_, // num_heads or batch_size x num_heads
const float p_dropout, // probability to drop
const float softmax_scale,
const bool is_causal,
int window_size_left,
int window_size_right,
const float softcap,
const bool deterministic,
c10::optional<at::Generator> gen_,
c10::optional<at::Tensor> &rng_state);
std::vector<at::Tensor>
mha_varlen_bwd(const at::Tensor &dout, // total_q x num_heads x head_size
const at::Tensor &q, // total_q x num_heads x head_size, total_q := \sum_{i=0}^{b} s_i
const at::Tensor &k, // total_k x num_heads_k x head_size, total_k := \sum_{i=0}^{b} s_i
const at::Tensor &v, // total_k x num_heads_k x head_size, total_k := \sum_{i=0}^{b} s_i
const at::Tensor &out, // total_q x num_heads x head_size
const at::Tensor &softmax_lse, // b x h x s softmax logsumexp
c10::optional<at::Tensor> &dq_, // total_q x num_heads x head_size, total_q := \sum_{i=0}^{b} s_i
c10::optional<at::Tensor> &dk_, // total_k x num_heads_k x head_size, total_k := \sum_{i=0}^{b} s_i
c10::optional<at::Tensor> &dv_, // total_k x num_heads_k x head_size, total_k := \sum_{i=0}^{b} s_i
const at::Tensor &cu_seqlens_q, // b+1
const at::Tensor &cu_seqlens_k, // b+1
c10::optional<at::Tensor> &alibi_slopes_, // num_heads or b x num_heads
const int max_seqlen_q,
const int max_seqlen_k, // max sequence length to choose the kernel
const float p_dropout, // probability to drop
const float softmax_scale,
const bool zero_tensors,
const bool is_causal,
int window_size_left,
int window_size_right,
const float softcap,
const bool deterministic,
c10::optional<at::Generator> gen_,
c10::optional<at::Tensor> &rng_state);
PYBIND11_MODULE(TORCH_EXTENSION_NAME, m)
{
m.doc() = "FlashAttention";
m.def("fwd", &mha_fwd, "Forward pass");
m.def("varlen_fwd", &mha_varlen_fwd, "Forward pass (variable length)");
m.def("bwd", &mha_bwd, "Backward pass");
m.def("varlen_bwd", &mha_varlen_bwd, "Backward pass (variable length)");
}