Man Pages

sched_rr_get_interval(2) - phpMan sched_rr_get_interval(2) - phpMan

Command: man perldoc info search(apropos)  

SCHED_RR_GET_INTERVAL(2)   Linux Programmer's Manual  SCHED_RR_GET_INTERVAL(2)

       sched_rr_get_interval - get the SCHED_RR interval for the named process

       #include <sched.h>

       int sched_rr_get_interval(pid_t pid, struct timespec * tp);

       sched_rr_get_interval()  writes  into  the timespec structure pointed to by tp the round-robin time quantum for
       the process identified by pid.

       The timespec structure has the following form:

           struct timespec {
               time_t tv_sec;    /* seconds */
               long   tv_nsec;   /* nanoseconds */

       If pid is zero, the time quantum for the calling process is written into *tp.  The identified process should be
       running  under  the  SCHED_RR  scheduling  policy.  POSIX systems on which sched_rr_get_interval() is available
       define _POSIX_PRIORITY_SCHEDULING in <unistd.h>.

       On success, sched_rr_get_interval() returns 0.  On error, -1 is returned, and errno is set appropriately.

       EFAULT Problem with copying information to userspace.

       EINVAL Invalid pid.

       ENOSYS The system call is not yet implemented (only on rather old kernels).

       ESRCH  The process whose ID is pid could not be found.


   Linux Notes
       POSIX does not specify any mechanism for controlling the size of the round-robin time quantum.  However,  Linux
       provides  a (non-portable) method of doing this.  The quantum can be controlled by adjusting the process's nice
       value (see setpriority(2)).  Assigning a negative (i.e., high) nice value results in a longer quantum;  assign-
       ing  a  positive  (i.e., low) nice value results in a shorter quantum.  The default quantum is 0.1 seconds; the
       degree to which changing the nice value affects the quantum has varied somewhat across kernel versions.

       sched_setscheduler(2) has a description of the Linux scheduling scheme.

       Programming for the  real  world  -  POSIX.4  by  Bill  O.  Gallmeister,  O'Reilly  &  Associates,  Inc.,  ISBN

       This  page  is part of release 3.22 of the Linux man-pages project.  A description of the project, and informa-
       tion about reporting bugs, can be found at

Linux                             2007-04-06          SCHED_RR_GET_INTERVAL(2)