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Revision a1e92fe78fe48925f83ffb20e6b577f5863d7faa authored by Jeff Mahoney on 05 June 2016, 00:21:04 UTC, committed by Jeff Mahoney on 05 June 2016, 00:21:04 UTC 
can_redirect: don't treat mkdir returning EEXIST as an error
 
can_redirect's test for existance of the path followed by the mkdir
is inherently racy.  It's trivially possible to encounter a situation
where the test for existance fails in two processes and one of them
succeeds in creating the directory.  Since both processes are
looking to create and use the directory for the same purpose, we
don't need to treat EEXIST as an error.
1 parent 7598fb9
Raw File
setcore_stubs.c 
#include "config.h"
#include <stdio.h>
#include <unistd.h>
#if HAVE_MACH_THREAD_POLICY_H
#include <mach/mach_init.h>
#include <mach/thread_policy.h>
// #include <mach/sched.h>
#endif
#if HAVE_DECL_SCHED_SETAFFINITY
//#define _GNU_SOURCE             /* See feature_test_macros(7) */
#include <sched.h>
#endif
#include <errno.h>
#include <caml/mlvalues.h>

CAMLprim value numcores(value unit) {
  int numcores = sysconf( _SC_NPROCESSORS_ONLN );
  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
#if HAVE_DECL_SCHED_SETAFFINITY
  cpu_set_t cpus;   
#endif
#if HAVE_MACH_THREAD_POLICY_H
  thread_affinity_policy_data_t affinityData;
#endif
  int retcode;
  int finished=0;
  while (finished==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;
	}
    }
  return Val_unit;
}
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