gperftools doesn't work

[kirillkh]

gperftools (aka Google Profiler) produces no useful output.

E.g., this code:

#include "gperftools/profiler.h"
#include <iostream>
#include <math.h>
using namespace std;
void bar()
{
  int a,b,c,d,j,k;
  a=0;
  int z=0;
  b = 1000;
  while(z < b)
    {
      while (a < b)
        {
          d = sin(a);
          c = cos(a);
          j = tan(a);
          k = tan(a);
          k = d * c + j *k;
          a++;
        }
      a = 0;
      z++;
    }
}

int main()
{
  ProfilerStart("prof.out");

  bar();
  ProfilerFlush();
  ProfilerStop();
}

produces the following output on a real Ubuntu machine:

$ CPUPROFILE=prof.out ./test
PROFILE: interrupts/evictions/bytes = 26/2/1848

but this output on WSL:

$ CPUPROFILE=prof.out ./test
PROFILE: interrupts/evictions/bytes = 0/0/64

Trying to dump prof.out indeed shows it is empty:

$ google-pprof ./test --svg prof.out
Using local file ./test.
Using local file prof.out.
No nodes to print

I tried running with various levels of PERFTOOLS_VERBOSE, but was not able to obtain any leads on where the problem might be.

[therealkenc]

Lead (given missing #include <gperftools/profiler.h>)...

strace -f ./test 2> test.strace

...
setitimer(ITIMER_PROF, {it_interval={0, 10000}, it_value={0, 10000}}, NULL) = -1 
   EINVAL (Invalid argument)
...

[kirillkh]

Sorry about the missing include, fixed.

[stehufntdev]

@therealkenc thanks for the great triage!

@kirillkh, WSL currently only supports ITIMER_REAL for setitimer. Please give us feedback for this scenario on the user voice page so we can prioritize - https://wpdev.uservoice.com/forums/266908-command-prompt-console-bash-on-ubuntu-on-windo/.

[kirillkh]

https://wpdev.uservoice.com/forums/266908-command-prompt-console-bash-on-ubuntu-on-windo/suggestions/17682463-support-gperftools