Question

在nvprof中，我可以看到我正在使用的每个cuda执行流的流ID（0,13,15等）

鉴于流变量，我希望能够打印出流ID。目前我找不到任何API来执行此操作并将cudaStream_t转换为int或uint不会产生合理的ID。 sizeof()表示cudaStream_t为8个字节。

Answer 1

简单地说：我不知道直接访问这些ID的方法，但您可以为流分析提供流明确的名称。

cudaStream_t是一个不透明的资源句柄＆＃34;类型。资源句柄类似于指针;所以可以理解的是，流ID不包含在指针（句柄）本身中，而是以某种方式包含在它所引用的内容中。

由于它是不透明的（没有CUDA提供的内容的定义），并且你指出没有直接的API，我不认为你会找到一种方法来提取运行时来自cudaStream_t的流ID。

对于cudaStream_t是资源句柄且不透明的这些断言，请参阅CUDA头文件driver_types.h

但是，the NV Tools Extension API为您提供了＆＃34; name＆＃34;特定流（或其他资源）。这将允许您将源代码中的特定流与分析器中的特定名称相关联。

这是一个微不足道的例子：

$ cat t138.cu
#include <stdio.h>
#include <nvToolsExtCudaRt.h>
const long tdel = 1000000000ULL;
__global__ void tkernel(){

  long st = clock64();
  while (clock64() < st+tdel);
}

int main(){

  cudaStream_t s1, s2, s3, s4;
  cudaStreamCreate(&s1);
  cudaStreamCreate(&s2);
  cudaStreamCreate(&s3);
  cudaStreamCreate(&s4);
#ifdef USE_S_NAMES
  nvtxNameCudaStreamA(s1, "stream 1");
  nvtxNameCudaStreamA(s2, "stream 2");
  nvtxNameCudaStreamA(s3, "stream 3");
  nvtxNameCudaStreamA(s4, "stream 4");
#endif
  tkernel<<<1,1,0,s1>>>();
  tkernel<<<1,1,0,s2>>>();
  tkernel<<<1,1,0,s3>>>();
  tkernel<<<1,1,0,s4>>>();

  cudaDeviceSynchronize();
}

$ nvcc -arch=sm_61 -o t138 t138.cu -lnvToolsExt
$ nvprof --print-gpu-trace ./t138
==28720== NVPROF is profiling process 28720, command: ./t138
==28720== Profiling application: ./t138
==28720== Profiling result:
   Start  Duration            Grid Size      Block Size     Regs*    SSMem*    DSMem*      Size  Throughput           Device   Context    Stream  Name
464.80ms  622.06ms              (1 1 1)         (1 1 1)         8        0B        0B         -           -  TITAN X (Pascal         1        13  tkernel(void) [393]
464.81ms  621.69ms              (1 1 1)         (1 1 1)         8        0B        0B         -           -  TITAN X (Pascal         1        14  tkernel(void) [395]
464.82ms  623.30ms              (1 1 1)         (1 1 1)         8        0B        0B         -           -  TITAN X (Pascal         1        15  tkernel(void) [397]
464.82ms  622.69ms              (1 1 1)         (1 1 1)         8        0B        0B         -           -  TITAN X (Pascal         1        16  tkernel(void) [399]

Regs: Number of registers used per CUDA thread. This number includes registers used internally by the CUDA driver and/or tools and can be more than what the compiler shows.
SSMem: Static shared memory allocated per CUDA block.
DSMem: Dynamic shared memory allocated per CUDA block.
$ nvcc -arch=sm_61 -o t138 t138.cu -lnvToolsExt -DUSE_S_NAMES
$ nvprof --print-gpu-trace ./t138
==28799== NVPROF is profiling process 28799, command: ./t138
==28799== Profiling application: ./t138
==28799== Profiling result:
   Start  Duration            Grid Size      Block Size     Regs*    SSMem*    DSMem*      Size  Throughput           Device   Context    Stream  Name
457.98ms  544.07ms              (1 1 1)         (1 1 1)         8        0B        0B         -           -  TITAN X (Pascal         1  stream 1  tkernel(void) [393]
457.99ms  544.31ms              (1 1 1)         (1 1 1)         8        0B        0B         -           -  TITAN X (Pascal         1  stream 2  tkernel(void) [395]
458.00ms  544.07ms              (1 1 1)         (1 1 1)         8        0B        0B         -           -  TITAN X (Pascal         1  stream 3  tkernel(void) [397]
458.00ms  544.07ms              (1 1 1)         (1 1 1)         8        0B        0B         -           -  TITAN X (Pascal         1  stream 4  tkernel(void) [399]

Regs: Number of registers used per CUDA thread. This number includes registers used internally by the CUDA driver and/or tools and can be more than what the compiler shows.
SSMem: Static shared memory allocated per CUDA block.
DSMem: Dynamic shared memory allocated per CUDA block.
$

如何使用cudaStream_t访问nvprof中看到的数字流ID？

1 个答案: