- Thread a cudaStream_t through attn dispatchers onto torch's current stream - Scope the device guard to the entry function so kernels run on tensor device - DISPATCH_HEAD_DIM now forwards varargs so stream reaches each dispatch - Parallelize CPU reference kernels with OpenMP (paged test 31s -> 7s) - Merge decode/prefill standalone tests into attn_test.cu with correctness tables - Drop bench error column (CPU ref too slow at large sizes) - Update cuda_kernels.md for the merged test layout
47 lines
1.5 KiB
Plaintext
47 lines
1.5 KiB
Plaintext
#include "attn_dispatchers.cuh"
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#include "attn_entry_utils.cuh"
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torch::Tensor attn_paged_decode(
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torch::Tensor q,
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torch::Tensor k_cache,
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torch::Tensor v_cache,
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torch::Tensor req_to_token,
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torch::Tensor req_pool_indices,
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torch::Tensor kv_indptr,
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int64_t max_seq_len,
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c10::optional<torch::Tensor> mask,
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int64_t causal_offset,
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double scale
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) {
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const at::cuda::OptionalCUDAGuard device_guard(device_of(q));
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auto stream = at::cuda::getCurrentCUDAStream();
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PagedAttentionParams<bf16> p;
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attn_pack_paged_decode_params(q, k_cache, v_cache,
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req_to_token, req_pool_indices, kv_indptr,
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max_seq_len, mask, causal_offset, scale, p);
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auto O = torch::empty({q.size(0), q.size(1), q.size(2)}, q.options());
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p.o = (bf16*)O.data_ptr();
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alloc_split_partials(p);
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DISPATCH_HEAD_DIM(p.head_dim, dispatch_paged_decode, p, stream);
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C10_CUDA_CHECK(cudaGetLastError());
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return O;
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}
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PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
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m.def("attn_paged_decode", &attn_paged_decode,
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py::arg("q"),
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py::arg("k_cache"),
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py::arg("v_cache"),
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py::arg("req_to_token"),
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py::arg("req_pool_indices"),
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py::arg("kv_indptr"),
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py::arg("max_seq_len"),
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py::arg("mask") = py::none(),
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py::arg("causal_offset") = -1,
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py::arg("scale") = 0.0,
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"SGLang-style paged decode: flat KV pool + req_to_token + kv_indptr.");
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}
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