无法获得处理器关联性（Linux）

Question

I am trying to take the affinity mask and make a comma separated string from it using CPU_ISSET(). Then, I need to add the string "taskset -c" in front of it and executable behind it in order to create a Linux command.

When I add the cpu numbers to the array and print it, the output is not correct.

I need the array to eventually output as a string in order to run the Linux command.

int main() {
   cpu_set_t mask;
   int temp[FILENAME_MAX]
   for(int i = 0; i < CPU_SETSIZE; i++)
   {
      if(CPU_ISSET(i, &mask))
      {
         temp[i] = i; 
      }
   }
   for(int i: temp)
      os << i;
   string str(os.str());
   cout << str;
   return 0;
}

output is a ton of zeros and then random numbers.

Answer 1

You forgot to load up your mask, which you can do like so:

sched_getaffinity (getpid (), CPU_SETSIZE, &mask);

That's all.

---

Edit:

I didn't notice before but those loops are flawed, even after your edit. For the first one, do something like:

for (int i = 0; i < CPU_SETSIZE; i++)
    temp [i] = (CPU_ISSET (i, &mask)) ? i : -1;

And for the second, do:

for (int i : temp)
{
    if (i >= 0)
        os << i;
}

And, of course, declare temp as:

int temp [CPU_SETSIZE];

Then you should start to get some sensible results.

Recommendation: pay more attention to detail. You're not going to get anywhere if you don't. And accepting this answer would be nice as I have tidied everything up for you.