sched_rr_get_interval(2) [debian man page]

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

NAME

       sched_rr_get_interval - get the SCHED_RR interval for the named process

SYNOPSIS

       #include <sched.h>

       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 specified process should be running under the SCHED_RR scheduling policy.

       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.

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 user space.

       EINVAL Invalid pid.

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

       ESRCH  Could not find a process with the ID pid.

CONFORMING TO

       POSIX.1-2001.

NOTES

       POSIX systems on which sched_rr_get_interval() is available define _POSIX_PRIORITY_SCHEDULING in <unistd.h>.

   Linux Notes
       POSIX does not specify any mechanism for controlling the size of the round-robin time quantum.  Older Linux kernels provide a (nonportable)
       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; assigning 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.  Since
       Linux 2.6.24, the SCHED_RR quantum cannot be modified.

SEE ALSO

       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 1-56592-074-0.

COLOPHON

       This page is part of release 3.44 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								    2011-10-16						  SCHED_RR_GET_INTERVAL(2)

Check Out this Related Man Page

SCHED_RR_GET_INTERVAL(3P)				     POSIX Programmer's Manual					 SCHED_RR_GET_INTERVAL(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       sched_rr_get_interval - get execution time limits (REALTIME)

SYNOPSIS

       #include <sched.h>

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

DESCRIPTION

       The sched_rr_get_interval() function shall update the timespec structure referenced by the interval argument to contain the current  execu-
       tion  time limit (that is, time quantum) for the process specified by pid. If pid is zero, the current execution time limit for the calling
       process shall be returned.

RETURN VALUE

       If successful, the sched_rr_get_interval() function shall return zero. Otherwise, it shall return a value of -1 and set errno  to  indicate
       the error.

ERRORS

       The sched_rr_get_interval() function shall fail if:

       ESRCH  No process can be found corresponding to that specified by pid.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       sched_getparam(),  sched_get_priority_max(),  sched_getscheduler(),  sched_setparam(), sched_setscheduler(), the Base Definitions volume of
       IEEE Std 1003.1-2001, <sched.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and  the  original  IEEE
       and  The  Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003						 SCHED_RR_GET_INTERVAL(3P)

Linux and UNIX Man Pages

sched_rr_get_interval(2) [debian man page]

Check Out this Related Man Page