As of about CUDA 3.0, runtime API device pointers (and everything else) are interoperable with the driver API. So yes, you can use cuMemsetD32
to fill a runtime API allocation with a 32 bit value. The size of CUdeviceptr
will match the size of void *
on you platform and it is safe to cast a pointer from the CUDA API to CUdeviceptr
or vice versa.
What's the 'right' way to implement a 32-bit memset for CUDA?
質問
CUDA has the API call
cudaError_t cudaMemset (void *devPtr, int value, size_t count)
which fills a buffer with a single-byte value. I want to fill it with a multi-byte value. Suppose, for the sake of simplicity, that I want to fill devPtr
with a 32-bit (4-byte) value, and suppose we can ignore endianness. Now, the CUDA driver has the following API call:
CUresult cuMemsetD32(CUdeviceptr dstDevice, unsigned int ui, size_t N)
So is it enough for me to just: obtain the CUdeviceptr
from the device-memory-space pointer, then make the driver API call? Or is there something else I need to be doing?
解決
他のヒント
Based on talonmies' answer, it seems a reasonable (though ugly) approach would be:
#include <stdint.h>
inline cudaError_t cudaMemsetTyped<T>(void *devPtr, T value, size_t count);
#define INSTANTIATE_CUDA_MEMSET_TYPED(_nbits) \
inline cudaError_t cudaMemsetTyped<int ## _nbits ## _t>(void *devPtr, int ## _nbits ## _t value, size_t count) { \
cuMemsetD ## _nbits( reinterpret_cast<CUdeviceptr>(devPtr), value, count); \
} \
inline cudaError_t cudaMemsetTyped<uint ## _nbits ## _t>(void *devPtr, uint ## _nbits ## _t value, size_t count) { \
cuMemsetD ## _nbits( reinterpret_cast<CUdeviceptr>(devPtr), reinterpret_cast<uint ## _nbits ## _t>(value), count); \
} \
INSTANTIATE_CUDA_MEMSET_TYPED(8)
INSTANTIATE_CUDA_MEMSET_TYPED(16)
INSTANTIATE_CUD_AMEMSET_TYPED(32)
#undef INSTANTIATE_CUDA_MEMSET_TYPED(_nbits)
inline cudaError_t cudaMemsetTyped<float>(void *devPtr, float value, size_t count) {
cuMemsetD32( reinterpret_cast<CUdeviceptr>(devPtr), reinterpret_cast<int>(value), count);
}
(no cuMemset64
it seems, so no double
either)
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