Files
triton-tvm-ffi/examples/attention/attnfwd.cc
2026-02-12 15:31:50 +08:00

53 lines
2.1 KiB
C++

#include <ATen/DLConvertor.h>
#include <ATen/core/ATen_fwd.h>
#include <ATen/dlpack.h>
#include <ATen/ops/empty.h>
#include <tvm/ffi/container/tensor.h>
#include <tvm/ffi/extra/cuda/cubin_launcher.h>
#include <tvm/ffi/function.h>
#include <tvm/ffi/tvm_ffi.h>
#ifndef _ATTN_FWD_STUB
#define _ATTN_FWD_STUB(grid, device, stream, args, kwargs)
#endif
#ifndef _ATTN_FWD_TVM_FFI_NAME
#define _ATTN_FWD_TVM_FFI_NAME ""
#endif
tvm::ffi::Tuple<tvm::ffi::Tensor, tvm::ffi::Tensor>
AttnFwd(tvm::ffi::Tensor q, tvm::ffi::Tensor k, tvm::ffi::Tensor v, bool casual,
float smScale) {
const tvm::ffi::ShapeView &qshape = q.shape(), &kshape = k.shape(),
&vshape = v.shape();
const int32_t kB = qshape[0], kH = qshape[1], kN = qshape[2], kQ = qshape[3],
kK = kshape[3], kV = vshape[3], stage = casual ? 3 : 1;
at::Tensor qTorch = at::fromDLPack(q.ToDLPack()),
oTorch = at::empty_like(qTorch),
mTorch =
at::empty({kB, kH, kN}, qTorch.options().dtype(at::kFloat));
tvm::ffi::Tensor o = tvm::ffi::Tensor::FromDLPack(at::toDLPack(oTorch)),
m = tvm::ffi::Tensor::FromDLPack(at::toDLPack(mTorch));
tvm::ffi::Function grid = tvm::ffi::Function::FromTyped(
[kB, kH, kN](const tvm::ffi::Map<tvm::ffi::String, tvm::ffi::Any> &meta)
-> tvm::ffi::Tuple<int32_t, int32_t, int32_t> {
const int32_t kBlockM = meta["BLOCK_M"].cast<int32_t>();
return tvm::ffi::Tuple<int32_t, int32_t, int32_t>(
(kN + kBlockM - 1) / kBlockM, kB * kH, 1);
});
tvm::ffi::Array<tvm::ffi::Any> args = {smScale, m, kB, kH, q, k, v, o, kN};
tvm::ffi::Map<tvm::ffi::String, tvm::ffi::Any> kwargs = {
{"HEAD_DIM", kK},
{"STAGE", stage},
};
DLDevice device = q.device();
void *stream = TVMFFIEnvGetStream(device.device_type, device.device_id);
_ATTN_FWD_STUB(grid, device.device_id, stream, args, kwargs);
return tvm::ffi::Tuple{m, o};
}
TVM_FFI_STATIC_INIT_BLOCK() {
namespace refl = tvm::ffi::reflection;
refl::GlobalDef().def(_ATTN_FWD_TVM_FFI_NAME, AttnFwd);
}