如何在OpenACC中找到帮派的ID? [英] How can I find the id of a gang in OpenACC?

问题描述

在OpenMP中，我可以使用omp_get_thread_num()来获取执行代码的线程的数字ID.

在OpenACC中是否可以使用类似的功能来获取执行一段代码的帮派的ID?

解决方案

OpenACC标准尚不包括这样的功能，但是对于PGI编译器，您可以如下使用编译器扩展功能__pgi_gangidx():

 //pgc++ -fast -acc -ta=tesla,cc60 -Minfo=accel test.cpp
#include <iostream>
#include "openacc.h"

int main(){
  int gangs = 100;
  int *ids  = new int[gangs];

  //Ensure everything is zeroed
  for(int i=0;i<gangs;i++)
    ids[i] = 0;

  #pragma acc parallel num_gangs(gangs) copyout(ids[0:gangs])
  {
    ids[__pgi_gangidx()] = __pgi_gangidx();
  }

  for(int i=0;i<gangs;i++)
    std::cout<<ids[i]<<" ";
  std::cout<<std::endl;
}
 

编译为:

pgc++ -fast -acc -ta=tesla,cc60 -Minfo=accel test.cpp

这给出了输出:

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

符合预期.

一系列附加功能可用:

 extern int __pgi_gangidx(void);
extern int __pgi_workeridx(void);
extern int __pgi_vectoridx(void);
extern int __pgi_blockidx(int);
extern int __pgi_threadidx(int);
 

请注意，omp_get_thread_num()不适用于GPU目标代码.

In OpenMP I can use omp_get_thread_num() to get the numerical id of the thread executing the code.

Is there a similar function I can use in OpenACC to get id of the gang executing a piece of code?

解决方案

The OpenACC standard does not yet include such a function, but, with the PGI compiler, you can use the compiler extension function __pgi_gangidx() as follows:

//pgc++ -fast -acc -ta=tesla,cc60 -Minfo=accel test.cpp
#include <iostream>
#include "openacc.h"

int main(){
  int gangs = 100;
  int *ids  = new int[gangs];

  //Ensure everything is zeroed
  for(int i=0;i<gangs;i++)
    ids[i] = 0;

  #pragma acc parallel num_gangs(gangs) copyout(ids[0:gangs])
  {
    ids[__pgi_gangidx()] = __pgi_gangidx();
  }

  for(int i=0;i<gangs;i++)
    std::cout<<ids[i]<<" ";
  std::cout<<std::endl;
}

Compile with:

pgc++ -fast -acc -ta=tesla,cc60 -Minfo=accel test.cpp

This gives as output:

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

as expected.

A suite of additional functions are available:

extern int __pgi_gangidx(void);
extern int __pgi_workeridx(void);
extern int __pgi_vectoridx(void);
extern int __pgi_blockidx(int);
extern int __pgi_threadidx(int);

Note that omp_get_thread_num() does not (yet?) work for GPU-targeted code.

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