39 lines
1.0 KiB
Plaintext
39 lines
1.0 KiB
Plaintext
#include <sgl_kernel/tensor.h>
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#include <sgl_kernel/utils.cuh>
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#include <cuda_runtime_api.h>
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#include <cstdint>
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namespace {
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__global__ void wait_flag_kernel(const int32_t* flag, int32_t target) {
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const volatile int32_t* vflag = (volatile const int32_t*)flag;
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while (*vflag != target) {
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#if __CUDA_ARCH__ >= 700
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__nanosleep(100);
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#else
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// Note: This falls back to an inefficient busy-wait on pre-Volta architectures.
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#endif
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}
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}
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auto stream_wait_value(const tvm::ffi::TensorView flag, std::int32_t value) -> void {
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using namespace host;
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auto length = SymbolicSize{"length"};
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TensorMatcher({length}).with_dtype<int32_t>().with_device<kDLCUDA>().verify(flag);
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RuntimeCheck(length.unwrap() >= 1, "wait_flag expects a non-empty tensor.");
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auto* ptr = static_cast<std::int32_t*>(flag.data_ptr());
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const auto stream = LaunchKernel::resolve_device(flag.device());
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constexpr int blocks = 1;
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constexpr int threads = 1;
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wait_flag_kernel<<<blocks, threads, 0, stream>>>(ptr, value);
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RuntimeDeviceCheck(cudaGetLastError());
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}
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} // namespace
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