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55 lines
2.0 KiB
55 lines
2.0 KiB
/*This code from NVIDIA Megatron:
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* with minor changes. */
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#include <cuda_fp16.h>
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#include <torch/extension.h>
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#include <vector>
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namespace multihead_attn {
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namespace fused_softmax {
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namespace scaled_upper_triang_masked_softmax {
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torch::Tensor fwd_cuda(torch::Tensor const& input, float scale_factor);
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torch::Tensor bwd_cuda(torch::Tensor const& output_grads,
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torch::Tensor const& softmax_results,
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float scale_factor);
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torch::Tensor fwd(torch::Tensor const& input, float scale_factor) {
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AT_ASSERTM(input.dim() == 3, "expected 3D tensor");
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AT_ASSERTM((input.scalar_type() == at::ScalarType::Half) ||
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(input.scalar_type() == at::ScalarType::BFloat16),
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"Only fp16 and bf16 are supported");
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return fwd_cuda(input, scale_factor);
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}
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torch::Tensor bwd(torch::Tensor const& output_grads,
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torch::Tensor const& softmax_results, float scale_factor) {
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AT_ASSERTM(output_grads.dim() == 3, "expected 3D tensor");
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AT_ASSERTM(softmax_results.dim() == 3, "expected 3D tensor");
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AT_ASSERTM((output_grads.scalar_type() == at::ScalarType::Half) ||
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(output_grads.scalar_type() == at::ScalarType::BFloat16),
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"Only fp16 and bf16 are supported");
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AT_ASSERTM((softmax_results.scalar_type() == at::ScalarType::Half) ||
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(softmax_results.scalar_type() == at::ScalarType::BFloat16),
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"Only fp16 and bf16 are supported");
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return bwd_cuda(output_grads, softmax_results, scale_factor);
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}
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} // end namespace scaled_upper_triang_masked_softmax
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} // end namespace fused_softmax
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} // end namespace multihead_attn
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PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
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m.def("forward",
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&multihead_attn::fused_softmax::scaled_upper_triang_masked_softmax::fwd,
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"Self Multihead Attention scaled, time masked softmax -- Forward.");
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m.def("backward",
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&multihead_attn::fused_softmax::scaled_upper_triang_masked_softmax::bwd,
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"Self Multihead Attention scaled, time masked softmax -- Backward.");
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}
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