2004-11-03 13:51:07 +00:00
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.\" Hey Emacs! This file is -*- nroff -*- source.
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.\"
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.\" Copyright (C) Tom Bjorkholm & Markus Kuhn, 1996
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.\"
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\"
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.\" The GNU General Public License's references to "object code"
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.\" and "executables" are to be interpreted as the output of any
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.\" document formatting or typesetting system, including
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.\" intermediate and printed output.
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.\"
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.\" This manual is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details.
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.\"
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.\" You should have received a copy of the GNU General Public
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.\" License along with this manual; if not, write to the Free
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.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
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.\" USA.
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.\"
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.\" 1996-04-01 Tom Bjorkholm <tomb@mydata.se>
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.\" First version written
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.\" 1996-04-10 Markus Kuhn <mskuhn@cip.informatik.uni-erlangen.de>
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.\" revision
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.\"
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2011-10-16 04:45:57 +00:00
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.TH SCHED_RR_GET_INTERVAL 2 2011-10-16 "Linux" "Linux Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.SH NAME
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2007-04-05 14:37:59 +00:00
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sched_rr_get_interval \- get the SCHED_RR interval for the named process
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2004-11-03 13:51:07 +00:00
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.SH SYNOPSIS
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.B #include <sched.h>
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.sp
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2007-07-16 18:57:34 +00:00
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.BI "int sched_rr_get_interval(pid_t " pid ", struct timespec * " tp );
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2004-11-03 13:51:07 +00:00
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.SH DESCRIPTION
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2005-10-19 06:54:38 +00:00
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.BR sched_rr_get_interval ()
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2011-10-16 04:50:04 +00:00
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writes into the
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.I timespec
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structure pointed to by
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.I tp
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the round-robin time quantum for the process identified by
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.IR pid .
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2011-10-16 04:45:57 +00:00
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The specified process should be running under the
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.B SCHED_RR
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scheduling policy.
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2007-04-05 12:50:59 +00:00
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2011-10-16 04:50:04 +00:00
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The
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.I timespec
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structure has the following form:
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2007-12-19 06:57:44 +00:00
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.in +4n
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.nf
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struct timespec {
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time_t tv_sec; /* seconds */
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long tv_nsec; /* nanoseconds */
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};
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.fi
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2007-04-05 14:37:59 +00:00
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.in
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2007-04-05 12:50:59 +00:00
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If
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2011-10-16 04:50:04 +00:00
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.I pid
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is zero, the time quantum for the calling process is written into
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.IR *tp .
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2008-04-23 09:10:40 +00:00
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.\" FIXME . On Linux, sched_rr_get_interval()
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.\" returns the timeslice for SCHED_OTHER processes -- this timeslice
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.\" is influenced by the nice value.
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.\" For SCHED_FIFO processes, this always returns 0.
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.\"
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2007-04-05 14:37:59 +00:00
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.\" The round-robin time quantum value is not alterable under Linux
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.\" 1.3.81.
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2007-04-12 22:42:49 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.SH "RETURN VALUE"
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On success,
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2005-10-19 06:54:38 +00:00
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.BR sched_rr_get_interval ()
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returns 0.
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On error, \-1 is returned, and
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.I errno
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is set appropriately.
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.SH ERRORS
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.TP
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.B EFAULT
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eventfd.2, futex.2, mmap2.2, open.2, pciconfig_read.2, ptrace.2, reboot.2, request_key.2, sched_rr_get_interval.2, splice.2, stat.2, sync_file_range.2, syscalls.2, timer_create.2, vm86.2, pthread_attr_setscope.3, core.5, proc.5, aio.7, futex.7, netlink.7, time.7: Global fix: "userspace" ==> "user space" or "user-space"
Existing pages variously use "userspace or "user space".
But, "userspace" is not quite an English word.
So change "userspace" to "user space" or, when used
attributively, "user-space".
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2012-10-21 06:04:42 +00:00
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Problem with copying information to user space.
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2004-11-03 13:51:07 +00:00
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.TP
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.B EINVAL
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Invalid pid.
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.TP
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.B ENOSYS
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2007-04-05 14:37:59 +00:00
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The system call is not yet implemented (only on rather old kernels).
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2004-11-03 13:51:07 +00:00
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.TP
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.B ESRCH
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2011-10-16 04:54:16 +00:00
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Could not find a process with the ID
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.IR pid .
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2004-11-03 13:51:07 +00:00
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.SH "CONFORMING TO"
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2006-08-03 13:57:17 +00:00
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POSIX.1-2001.
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2007-05-18 10:39:45 +00:00
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.SH NOTES
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2011-10-16 04:45:57 +00:00
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POSIX systems on which
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.BR sched_rr_get_interval ()
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is available define
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.B _POSIX_PRIORITY_SCHEDULING
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2011-10-16 04:50:04 +00:00
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in
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.IR <unistd.h> .
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intro.1, time.1, _syscall.2, accept.2, brk.2, capget.2, faccessat.2, futimesat.2, gethostname.2, intro.2, ioprio_set.2, kill.2, madvise.2, mlock.2, mount.2, msgget.2, perf_event_open.2, poll.2, readv.2, sched_rr_get_interval.2, sched_setscheduler.2, select.2, select_tut.2, shmget.2, stat.2, timer_create.2, ustat.2, vfork.2, wait.2, alloca.3, atexit.3, catopen.3, crypt.3, dbopen.3, fenv.3, fopen.3, getaddrinfo_a.3, gethostbyname.3, getutent.3, intro.3, login.3, mallopt.3, queue.3, regex.3, sigpause.3, sigsetops.3, stdio.3, strftime.3, strptime.3, sysconf.3, ttyslot.3, undocumented.3, cciss.4, console_codes.4, hpsa.4, initrd.4, intro.4, rtc.4, st.4, tty_ioctl.4, wavelan.4, acct.5, charmap.5, dir_colors.5, hosts.5, intro.5, termcap.5, utmp.5, intro.6, armscii-8.7, boot.7, bootparam.7, capabilities.7, cpuset.7, credentials.7, ddp.7, epoll.7, glob.7, intro.7, ip.7, ipv6.7, iso_8859-1.7, iso_8859-10.7, iso_8859-11.7, iso_8859-13.7, iso_8859-14.7, iso_8859-15.7, iso_8859-16.7, iso_8859-2.7, iso_8859-3.7, iso_8859-4.7, iso_8859-5.7, iso_8859-6.7, iso_8859-7.7, iso_8859-8.7, iso_8859-9.7, koi8-r.7, koi8-u.7, man-pages.7, man.7, math_error.7, netlink.7, numa.7, packet.7, path_resolution.7, pipe.7, pthreads.7, raw.7, rtnetlink.7, signal.7, socket.7, spufs.7, svipc.7, tcp.7, time.7, udp.7, udplite.7, unicode.7, unix.7, uri.7, utf-8.7, x25.7, intro.8: Global fix: use consistent capitalization in .SS headings
Capitalization in .SS sections across pages (and sometimes even
within a single page) is wildly inconsistent. Make it consistent.
Capitalize first word in heading, but otherwise use lower case,
except where English usage (e.g., proper nouns) or programming
language requirements (e.g., identifier names) dictate otherwise.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-02-24 14:08:38 +00:00
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.SS Linux notes
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2007-04-05 14:37:59 +00:00
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POSIX does not specify any mechanism for controlling the size of the
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round-robin time quantum.
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2011-10-16 05:01:47 +00:00
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Older Linux kernels provide a (nonportable) method of doing this.
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2007-04-05 14:37:59 +00:00
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The quantum can be controlled by adjusting the process's nice value (see
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.BR setpriority (2)).
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Assigning a negative (i.e., high) nice value results in a longer quantum;
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assigning a positive (i.e., low) nice value results in a shorter quantum.
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The default quantum is 0.1 seconds;
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2007-04-12 22:42:49 +00:00
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the degree to which changing the nice value affects the
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2007-04-05 14:37:59 +00:00
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quantum has varied somewhat across kernel versions.
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2011-10-16 05:01:47 +00:00
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Since Linux 2.6.24,
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.\" commit a4ec24b48ddef1e93f7578be53270f0b95ad666c
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the
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.BR SCHED_RR
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quantum cannot be modified.
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2007-04-05 14:37:59 +00:00
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.\" .SH BUGS
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2007-06-21 22:55:04 +00:00
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.\" As of Linux 1.3.81
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2007-05-12 12:53:57 +00:00
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.\" .BR sched_rr_get_interval ()
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.\" returns with error
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2007-04-05 14:37:59 +00:00
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.\" ENOSYS, because SCHED_RR has not yet been fully implemented and tested
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.\" properly.
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2004-11-03 13:51:07 +00:00
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.SH "SEE ALSO"
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.BR sched_setscheduler (2)
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has a description of the Linux scheduling scheme.
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.PP
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.I Programming for the real world \- POSIX.4
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arch_prctl.2, fcntl.2, flock.2, get_robust_list.2, getpriority.2, ioprio_set.2, migrate_pages.2, mmap.2, mremap.2, msync.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, select.2, socket.2, subpage_prot.2, unshare.2, btree.3, dbopen.3, dl_iterate_phdr.3, dlopen.3, getnameinfo.3, hash.3, lockf.3, netlink.3, recno.3, rpc.3, xdr.3, cciss.4, console_ioctl.4, hpsa.4, initrd.4, msr.4, rtc.4, st.4, hosts.5, services.5, tzfile.5, aio.7, arp.7, capabilities.7, cpuset.7, feature_test_macros.7, futex.7, inotify.7, ip.7, ipv6.7, iso_8859-16.7, iso_8859-2.7, koi8-r.7, math_error.7, netlink.7, packet.7, pthreads.7, raw.7, spufs.7, udplite.7, uri.7, x25.7: Global fix: Various consistency fixes for SEE ALSO
Coauthored-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2012-09-24 07:53:22 +00:00
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by Bill O. Gallmeister, O'Reilly & Associates, Inc., ISBN 1-56592-074-0.
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