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* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
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* contributors may be used to endorse or promote products derived
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*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
// std::system includes
#include <cstdio>
// CUDA-C includes
#include <cuda_runtime.h>
#include <helper_cuda.h>
#define TOTAL_SIZE 256 * 1024 * 1024
#define EACH_SIZE 128 * 1024 * 1024
// # threadblocks
#define TBLOCKS 1024
#define THREADS 512
// throw error on equality
#define ERR_EQ(X, Y) \
do { \
if ((X) == (Y)) { \
fprintf(stderr, "Error in %s at %s:%d\n", __func__, __FILE__, __LINE__); \
exit(-1); \
} \
} while (0)
// throw error on difference
#define ERR_NE(X, Y) \
do { \
if ((X) != (Y)) { \
fprintf(stderr, "Error in %s at %s:%d\n", __func__, __FILE__, __LINE__); \
exit(-1); \
} \
} while (0)
// copy from source -> destination arrays
__global__ void memcpy_kernel(int *dst, int *src, size_t n) {
int num = gridDim.x * blockDim.x;
int id = blockDim.x * blockIdx.x + threadIdx.x;
for (int i = id; i < n / sizeof(int); i += num) {
dst[i] = src[i];
}
}
// initialise memory
void mem_init(int *buf, size_t n) {
for (int i = 0; i < n / sizeof(int); i++) {
buf[i] = i;
}
}
int main(int argc, char **argv) {
cudaDeviceProp device_prop;
int dev_id;
printf("Starting [%s]...\n", argv[0]);
// set device
dev_id = findCudaDevice(argc, (const char **)argv);
checkCudaErrors(cudaGetDeviceProperties(&device_prop, dev_id));
if ((device_prop.major << 4) + device_prop.minor < 0x35) {
fprintf(stderr,
"%s requires Compute Capability of SM 3.5 or higher to "
"run.\nexiting...\n",
argv[0]);
exit(EXIT_WAIVED);
}
// get the range of priorities available
// [ greatest_priority, lowest_priority ]
int priority_low;
int priority_hi;
checkCudaErrors(
cudaDeviceGetStreamPriorityRange(&priority_low, &priority_hi));
printf("CUDA stream priority range: LOW: %d to HIGH: %d\n", priority_low,
priority_hi);
// create streams with highest and lowest available priorities
cudaStream_t st_low;
cudaStream_t st_hi;
checkCudaErrors(cudaStreamCreateWithPriority(&st_low, cudaStreamNonBlocking,
priority_low));
checkCudaErrors(
cudaStreamCreateWithPriority(&st_hi, cudaStreamNonBlocking, priority_hi));
size_t size;
size = TOTAL_SIZE;
// initialise host data
int *h_src_low;
int *h_src_hi;
ERR_EQ(h_src_low = (int *)malloc(size), NULL);
ERR_EQ(h_src_hi = (int *)malloc(size), NULL);
mem_init(h_src_low, size);
mem_init(h_src_hi, size);
// initialise device data
int *h_dst_low;
int *h_dst_hi;
ERR_EQ(h_dst_low = (int *)malloc(size), NULL);
ERR_EQ(h_dst_hi = (int *)malloc(size), NULL);
memset(h_dst_low, 0, size);
memset(h_dst_hi, 0, size);
// copy source data -> device
int *d_src_low;
int *d_src_hi;
checkCudaErrors(cudaMalloc(&d_src_low, size));
checkCudaErrors(cudaMalloc(&d_src_hi, size));
checkCudaErrors(
cudaMemcpy(d_src_low, h_src_low, size, cudaMemcpyHostToDevice));
checkCudaErrors(cudaMemcpy(d_src_hi, h_src_hi, size, cudaMemcpyHostToDevice));
// allocate memory for memcopy destination
int *d_dst_low;
int *d_dst_hi;
checkCudaErrors(cudaMalloc(&d_dst_low, size));
checkCudaErrors(cudaMalloc(&d_dst_hi, size));
// create some events
cudaEvent_t ev_start_low;
cudaEvent_t ev_start_hi;
cudaEvent_t ev_end_low;
cudaEvent_t ev_end_hi;
checkCudaErrors(cudaEventCreate(&ev_start_low));
checkCudaErrors(cudaEventCreate(&ev_start_hi));
checkCudaErrors(cudaEventCreate(&ev_end_low));
checkCudaErrors(cudaEventCreate(&ev_end_hi));
/* */
// call pair of kernels repeatedly (with different priority streams)
checkCudaErrors(cudaEventRecord(ev_start_low, st_low));
checkCudaErrors(cudaEventRecord(ev_start_hi, st_hi));
for (int i = 0; i < TOTAL_SIZE; i += EACH_SIZE) {
int j = i / sizeof(int);
memcpy_kernel<<<TBLOCKS, THREADS, 0, st_low>>>(d_dst_low + j, d_src_low + j,
EACH_SIZE);
memcpy_kernel<<<TBLOCKS, THREADS, 0, st_hi>>>(d_dst_hi + j, d_src_hi + j,
EACH_SIZE);
}
checkCudaErrors(cudaEventRecord(ev_end_low, st_low));
checkCudaErrors(cudaEventRecord(ev_end_hi, st_hi));
checkCudaErrors(cudaEventSynchronize(ev_end_low));
checkCudaErrors(cudaEventSynchronize(ev_end_hi));
/* */
size = TOTAL_SIZE;
checkCudaErrors(
cudaMemcpy(h_dst_low, d_dst_low, size, cudaMemcpyDeviceToHost));
checkCudaErrors(cudaMemcpy(h_dst_hi, d_dst_hi, size, cudaMemcpyDeviceToHost));
// check results of kernels
ERR_NE(memcmp(h_dst_low, h_src_low, size), 0);
ERR_NE(memcmp(h_dst_hi, h_src_hi, size), 0);
// check timings
float ms_low;
float ms_hi;
checkCudaErrors(cudaEventElapsedTime(&ms_low, ev_start_low, ev_end_low));
checkCudaErrors(cudaEventElapsedTime(&ms_hi, ev_start_hi, ev_end_hi));
printf("elapsed time of kernels launched to LOW priority stream: %.3lf ms\n",
ms_low);
printf("elapsed time of kernels launched to HI priority stream: %.3lf ms\n",
ms_hi);
exit(EXIT_SUCCESS);
}