src/psched.c

   1 /*
   2  * nao-ulib
   3  * Copyright 2011 Daniel Borkmann <dborkma@tik.ee.ethz.ch>
   4  * Subject to the GPL.
   5  * Nao-Team HTWK,
   6  * Faculty of Computer Science, Mathematics and Natural Sciences,
   7  * Leipzig University of Applied Sciences (HTWK Leipzig)
   8  */
   9
  10 #define _GNU_SOURCE
  11 #include <sys/types.h>
  12 #include <unistd.h>
  13 #include <sched.h>
  14
  15 #include "die.h"
  16 #include "psched.h"
  17
  18 void run_on_cpu(int cpu)
  19 {
  20         cpu_set_t mask;
  21
  22         CPU_ZERO(&mask);
  23         CPU_SET(cpu, &mask);
  24
  25         sched_setaffinity(0, sizeof(mask), &mask);
  26 }
  27
  28 int set_proc_prio(int priority)
  29 {
  30         /*
  31          * setpriority() is clever, even if you put a nice value which
  32          * is out of range it corrects it to the closest valid nice value
  33          */
  34         int ret = setpriority(PRIO_PROCESS, getpid(), priority);
  35         if (ret)
  36                 panic("Can't set nice val to %i!\n", priority);
  37
  38         return 0;
  39 }
  40
  41 int set_sched_status(int policy, int priority)
  42 {
  43         int ret, min_prio, max_prio;
  44         struct sched_param sp;
  45
  46         max_prio = sched_get_priority_max(policy);
  47         min_prio = sched_get_priority_min(policy);
  48
  49         if (max_prio == -1 || min_prio == -1)
  50                 whine("Cannot determine scheduler prio limits!\n");
  51         else if (priority < min_prio)
  52                 priority = min_prio;
  53         else if (priority > max_prio)
  54                 priority = max_prio;
  55
  56         memset(&sp, 0, sizeof(sp));
  57         sp.sched_priority = priority;
  58
  59         ret = sched_setscheduler(getpid(), policy, &sp);
  60         if (ret) {
  61                 whine("Cannot set scheduler policy!\n");
  62                 return -EINVAL;
  63         }
  64
  65         ret = sched_setparam(getpid(), &sp);
  66         if (ret) {
  67                 whine("Cannot set scheduler prio!\n");
  68                 return -EINVAL;
  69         }
  70
  71         return 0;
  72 }
  73