SCHED_RR_GET_INTERVAL(2)   Linux Programmers Manual  SCHED_RR_GET_INTERVAL(2)



NAME
       sched_rr_get_interval - get the SCHED_RR interval for the named process

SYNOPSIS
       #include 

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

DESCRIPTION
       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 .

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

ERRORS
       EFAULT Problem with copying information to userspace.

       EINVAL Invalid pid.

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

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

CONFORMING TO
       POSIX.1-2001.

NOTES
   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
       processs nice value (see setpriority(2)).  Assigning a negative (i.e.,
       high) nice value results in a  longer  quantum;	assigning  a  positive
       (i.e., low) nice value results in a shorter quantum.  The default quan
       tum is 0.1 seconds; the degree to which changing the nice value affects
       the quantum has varied somewhat across kernel versions.

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

       Programming for the real  world	-  POSIX.4  by	Bill  O.  Gallmeister,
       OReilly & Associates, Inc., ISBN 1-56592-074-0

COLOPHON
       This  page  is  part of release 3.05 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



Linux				  2007-04-06	      SCHED_RR_GET_INTERVAL(2)