Skip to content

Avoid looping forever if core pinning fails #104

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 1 commit into
base: master
Choose a base branch
from
Open

Avoid looping forever if core pinning fails #104

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
63 changes: 30 additions & 33 deletions src/setcore_stubs.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,47 +18,44 @@ CAMLprim value numcores(value unit) {
return Val_int(numcores);
}

CAMLprim value setcore(value which) {
int numcores = sysconf( _SC_NPROCESSORS_ONLN );
int w = Int_val(which) % numcores; // stay in the space of existing cores
int setcorew(int w) {
#if HAVE_DECL_SCHED_SETAFFINITY
cpu_set_t cpus;
#endif
#if HAVE_MACH_THREAD_POLICY_H
cpu_set_t cpus;
CPU_ZERO(&cpus);
CPU_SET (w,&cpus);
//fprintf(stderr,"Trying to pin to cpu %d out of %d reported by the system\n",w,numcores);
return sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpus);
#elif HAVE_MACH_THREAD_POLICY_H
thread_affinity_policy_data_t affinityData;
affinityData.affinity_tag = w;
return thread_policy_set(mach_thread_self(),
THREAD_AFFINITY_POLICY,
&affinityData,
THREAD_AFFINITY_POLICY_COUNT);
#else
return 0; // fake success
#endif
}

CAMLprim value setcore(value which) {
int numcores = sysconf( _SC_NPROCESSORS_ONLN );
int w = Int_val(which) % numcores; // stay in the space of existing cores
int retcode;
int finished=0;
if (numcores <= 1) // only one core in the system, no need to attempt pinning
return Val_unit;
while (finished==0)
do
{
retcode = setcorew(w);
if(retcode != 0)
{
#if HAVE_DECL_SCHED_SETAFFINITY
CPU_ZERO(&cpus);
CPU_SET (w,&cpus);
//fprintf(stderr,"Trying to pin to cpu %d out of %d reported by the system\n",w,numcores);
retcode = sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpus);
if(retcode != 0) {
fprintf(stderr,"Failed pinning to cpu %d, trying %d/2\n",w, w);
w=w/2;
}
else
#endif
#if HAVE_MACH_THREAD_POLICY_H
affinityData.affinity_tag = w;
retcode = thread_policy_set(mach_thread_self(),
THREAD_AFFINITY_POLICY,
&affinityData,
THREAD_AFFINITY_POLICY_COUNT);
if(retcode) {
fprintf(stderr,"MAC OS X: Failed pinning to cpu %d, trying %d/2\n",w, w);
w=w/2;
}
else
#endif
{ //fprintf(stderr,"Succeeded pinning to cpu %d\n",w);
finished=1;
}
fprintf(stderr,"Failed pinning to cpu %d, trying %d/2\n",w, w);
w=w/2;
}
else
{ //fprintf(stderr,"Succeeded pinning to cpu %d\n",w);
finished=1;
}
} while (finished==0 && w>0);
return Val_unit;
}