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Probe the CUDA special registers %smid and %nsmid.
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#include <stdio.h> | |
// | |
// | |
// | |
#define DEVICE_INTRINSIC_QUALIFIERS __device__ __forceinline__ | |
DEVICE_INTRINSIC_QUALIFIERS | |
unsigned int | |
smid() | |
{ | |
unsigned int r; | |
asm("mov.u32 %0, %%smid;" : "=r"(r)); | |
return r; | |
} | |
DEVICE_INTRINSIC_QUALIFIERS | |
unsigned int | |
nsmid() | |
{ | |
#if (__CUDA_ARCH__ >= 200) | |
unsigned int r; | |
asm("mov.u32 %0, %%nsmid;" : "=r"(r)); | |
return r; | |
#else | |
return 30; | |
#endif | |
} | |
// | |
// | |
// | |
__device__ int g_nsmid[1]; | |
__device__ int g_smid[64] = { | |
-1, -1, -1, -1, -1, -1, -1, -1, | |
-1, -1, -1, -1, -1, -1, -1, -1, | |
-1, -1, -1, -1, -1, -1, -1, -1, | |
-1, -1, -1, -1, -1, -1, -1, -1, | |
-1, -1, -1, -1, -1, -1, -1, -1, | |
-1, -1, -1, -1, -1, -1, -1, -1, | |
-1, -1, -1, -1, -1, -1, -1, -1, | |
-1, -1, -1, -1, -1, -1, -1, -1 | |
}; | |
// | |
// | |
// | |
__global__ | |
void | |
smidTest() | |
{ | |
const int n = nsmid(); | |
const int s = smid(); | |
g_nsmid[0] = n; | |
g_smid[s] = s; | |
} | |
// | |
// | |
// | |
int main(int argc, char **argv) | |
{ | |
cudaError_t err; | |
int device = (argc == 1) ? 0 : atoi(argv[1]); | |
cudaDeviceProp props; | |
err = cudaGetDeviceProperties(&props,device); | |
if (err) | |
return -1; | |
// if (props.major < 2) { | |
// printf("%s = sm_%d%d\n",props.name,props.major,props.minor); | |
// return -1; | |
// } | |
cudaSetDevice(device); | |
// | |
// LAUNCH KERNEL | |
// | |
smidTest<<<props.multiProcessorCount,1,props.sharedMemPerBlock-384>>>(); | |
cudaDeviceSynchronize(); | |
// | |
// LOOK AT RESULTS | |
// | |
int h_nsmid[1]; | |
int h_smid[48]; | |
cudaMemcpyFromSymbol(h_nsmid,g_nsmid,sizeof(h_nsmid)); | |
cudaMemcpyFromSymbol(h_smid, g_smid, sizeof(h_smid)); | |
// | |
// | |
// | |
printf("%s (%2d) [ %2d", | |
props.name, | |
(h_nsmid[0] == 30) ? props.multiProcessorCount : h_nsmid[0], | |
h_smid[0]); | |
int last = 0; | |
for (int ii=1; ii<h_nsmid[0]; ii++) | |
{ | |
if (h_smid[ii] != -1) | |
last = ii; | |
} | |
for (int ii=1; ii<=last; ii++) | |
{ | |
const int s = h_smid[ii]; | |
if (s == -1) | |
printf(", --"); | |
else | |
printf(", %2d",s); | |
} | |
printf(" ]\n"); | |
// | |
// | |
// | |
return 0; | |
} |
Some results:
Tesla K20c (13) [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ]
GeForce GT 240 (12) [ 0, 1, 2, --, 4, 5, 6, --, 8, 9, 10, --, 12, 13, 14, ... ]
GeForce GTX 680 ( 8) [ 0, 1, 2, 3, 4, 5, 6, 7 ]
GeForce GT 545 ( 3) [ 0, 1, 2 ]
GeForce 9400 GT ( 4) [ 0, 1, --, --, 4, 5, ... ]
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