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>.
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 kernels).
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 quantum is 0.1 seconds;
the degree to which changing the nice value affects the
quantum has varied somewhat across kernel versions.
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 3.14 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/.