Man Sched_rr_get_interval en anglais
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 

       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
       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 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,
       O'Reilly & 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)