+++ /dev/null
-.\" Copyright (C) 2014 Michael Kerrisk <mtk.manpages@gmail.com>
-.\" and Copyright (C) 2014 Peter Zijlstra <peterz@infradead.org>
-.\" and Copyright (C) 2014 Juri Lelli <juri.lelli@gmail.com>
-.\" Various pieces from the old sched_setscheduler(2) page
-.\" Copyright (C) Tom Bjorkholm, Markus Kuhn & David A. Wheeler 1996-1999
-.\" and Copyright (C) 2007 Carsten Emde <Carsten.Emde@osadl.org>
-.\" and Copyright (C) 2008 Michael Kerrisk <mtk.manpages@gmail.com>
-.\"
-.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
-.\" This is free documentation; you can redistribute it and/or
-.\" modify it under the terms of the GNU General Public License as
-.\" published by the Free Software Foundation; either version 2 of
-.\" the License, or (at your option) any later version.
-.\"
-.\" The GNU General Public License's references to "object code"
-.\" and "executables" are to be interpreted as the output of any
-.\" document formatting or typesetting system, including
-.\" intermediate and printed output.
-.\"
-.\" This manual is distributed in the hope that it will be useful,
-.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
-.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-.\" GNU General Public License for more details.
-.\"
-.\" You should have received a copy of the GNU General Public
-.\" License along with this manual; if not, see
-.\" <http://www.gnu.org/licenses/>.
-.\" %%%LICENSE_END
-.\"
-.\" Worth looking at: http://rt.wiki.kernel.org/index.php
-.\"
-.TH SCHED 7 2014-10-02 "Linux" "Linux Programmer's Manual"
-.SH NAME
-sched \- overview of scheduling APIs
-.SH DESCRIPTION
-.SS API summary
-The Linux scheduling APIs are as follows:
-.TP
-.BR sched_setscheduler (2)
-Set the scheduling policy and parameters of a specified thread.
-.TP
-.BR sched_getscheduler (2)
-Return the scheduling policy of a specified thread.
-.TP
-.BR sched_setparam (2)
-Set the scheduling parameters of a specified thread.
-.TP
-.BR sched_getparam (2)
-Fetch the scheduling parameters of a specified thread.
-.TP
-.BR sched_get_priority_max (2)
-Return the minimum priority available in a specified scheduling policy.
-.TP
-.BR sched_get_priority_min (2)
-Return the maximum priority available in a specified scheduling policy.
-.TP
-.BR sched_rr_get_interval (2)
-Fetch the quantum used for threads that are scheduled under
-the "round-robin" scheduling policy.
-.TP
-.BR sched_yield (2)
-Cause the caller to relinquish the CPU,
-so that some other thread be executed.
-.TP
-.BR sched_setaffinity (2)
-(Linux-specific)
-Set the CPU affinity of a specified thread.
-.TP
-.BR sched_getaffinity (2)
-(Linux-specific)
-Get the CPU affinity of a specified thread.
-.TP
-.BR sched_setattr (2)
-Set the scheduling policy and parameters of a specified thread.
-This (Linux-specific) system call provides a superset of the functionality of
-.BR sched_setscheduler (2)
-and
-.BR sched_setparam (2).
-.TP
-.BR sched_getattr (2)
-Fetch the scheduling policy and parameters of a specified thread.
-This (Linux-specific) system call provides a superset of the functionality of
-.BR sched_getscheduler (2)
-and
-.BR sched_getparam (2).
-.\"
-.SS Scheduling policies
-The scheduler is the kernel component that decides which runnable thread
-will be executed by the CPU next.
-Each thread has an associated scheduling policy and a \fIstatic\fP
-scheduling priority,
-.IR sched_priority .
-The scheduler makes its decisions based on knowledge of the scheduling
-policy and static priority of all threads on the system.
-
-For threads scheduled under one of the normal scheduling policies
-(\fBSCHED_OTHER\fP, \fBSCHED_IDLE\fP, \fBSCHED_BATCH\fP),
-\fIsched_priority\fP is not used in scheduling
-decisions (it must be specified as 0).
-
-Processes scheduled under one of the real-time policies
-(\fBSCHED_FIFO\fP, \fBSCHED_RR\fP) have a
-\fIsched_priority\fP value in the range 1 (low) to 99 (high).
-(As the numbers imply, real-time threads always have higher priority
-than normal threads.)
-Note well: POSIX.1-2001 requires an implementation to support only a
-minimum 32 distinct priority levels for the real-time policies,
-and some systems supply just this minimum.
-Portable programs should use
-.BR sched_get_priority_min (2)
-and
-.BR sched_get_priority_max (2)
-to find the range of priorities supported for a particular policy.
-
-Conceptually, the scheduler maintains a list of runnable
-threads for each possible \fIsched_priority\fP value.
-In order to determine which thread runs next, the scheduler looks for
-the nonempty list with the highest static priority and selects the
-thread at the head of this list.
-
-A thread's scheduling policy determines
-where it will be inserted into the list of threads
-with equal static priority and how it will move inside this list.
-
-All scheduling is preemptive: if a thread with a higher static
-priority becomes ready to run, the currently running thread
-will be preempted and
-returned to the wait list for its static priority level.
-The scheduling policy determines the
-ordering only within the list of runnable threads with equal static
-priority.
-.SS SCHED_FIFO: First in-first out scheduling
-\fBSCHED_FIFO\fP can be used only with static priorities higher than
-0, which means that when a \fBSCHED_FIFO\fP threads becomes runnable,
-it will always immediately preempt any currently running
-\fBSCHED_OTHER\fP, \fBSCHED_BATCH\fP, or \fBSCHED_IDLE\fP thread.
-\fBSCHED_FIFO\fP is a simple scheduling
-algorithm without time slicing.
-For threads scheduled under the
-\fBSCHED_FIFO\fP policy, the following rules apply:
-.IP * 3
-A \fBSCHED_FIFO\fP thread that has been preempted by another thread of
-higher priority will stay at the head of the list for its priority and
-will resume execution as soon as all threads of higher priority are
-blocked again.
-.IP *
-When a \fBSCHED_FIFO\fP thread becomes runnable, it
-will be inserted at the end of the list for its priority.
-.IP *
-A call to
-.BR sched_setscheduler (2),
-.BR sched_setparam (2),
-or
-.BR sched_setattr (2)
-will put the
-\fBSCHED_FIFO\fP (or \fBSCHED_RR\fP) thread identified by
-\fIpid\fP at the start of the list if it was runnable.
-As a consequence, it may preempt the currently running thread if
-it has the same priority.
-(POSIX.1-2001 specifies that the thread should go to the end
-of the list.)
-.\" In 2.2.x and 2.4.x, the thread is placed at the front of the queue
-.\" In 2.0.x, the Right Thing happened: the thread went to the back -- MTK
-.IP *
-A thread calling
-.BR sched_yield (2)
-will be put at the end of the list.
-.PP
-No other events will move a thread
-scheduled under the \fBSCHED_FIFO\fP policy in the wait list of
-runnable threads with equal static priority.
-
-A \fBSCHED_FIFO\fP
-thread runs until either it is blocked by an I/O request, it is
-preempted by a higher priority thread, or it calls
-.BR sched_yield (2).
-.SS SCHED_RR: Round-robin scheduling
-\fBSCHED_RR\fP is a simple enhancement of \fBSCHED_FIFO\fP.
-Everything
-described above for \fBSCHED_FIFO\fP also applies to \fBSCHED_RR\fP,
-except that each thread is allowed to run only for a maximum time
-quantum.
-If a \fBSCHED_RR\fP thread has been running for a time
-period equal to or longer than the time quantum, it will be put at the
-end of the list for its priority.
-A \fBSCHED_RR\fP thread that has
-been preempted by a higher priority thread and subsequently resumes
-execution as a running thread will complete the unexpired portion of
-its round-robin time quantum.
-The length of the time quantum can be
-retrieved using
-.BR sched_rr_get_interval (2).
-.\" On Linux 2.4, the length of the RR interval is influenced
-.\" by the process nice value -- MTK
-.\"
-.SS SCHED_DEADLINE: Sporadic task model deadline scheduling
-Since version 3.14, Linux provides a deadline scheduling policy
-.RB ( SCHED_DEADLINE ).
-This policy is currently implemented using
-GEDF (Global Earliest Deadline First)
-in conjunction with CBS (Constant Bandwidth Server).
-To set and fetch this policy and associated attributes,
-one must use the Linux-specific
-.BR sched_setattr (2)
-and
-.BR sched_getattr (2)
-system calls.
-
-A sporadic task is one that has a sequence of jobs, where each
-job is activated at most once per period.
-Each job also has a
-.IR "relative deadline" ,
-before which it should finish execution, and a
-.IR "computation time" ,
-which is the CPU time necessary for executing the job.
-The moment when a task wakes up
-because a new job has to be executed is called the
-.IR "arrival time"
-(also referred to as the request time or release time).
-The
-.IR "start time"
-is the time at which a task starts its execution.
-The
-.I "absolute deadline"
-is thus obtained by adding the relative deadline to the arrival time.
-
-The following diagram clarifies these terms:
-
-.in +4n
-.nf
-arrival/wakeup absolute deadline
- | start time |
- | | |
- v v v
------x--------xooooooooooooooooo--------x--------x---
- |<- comp. time ->|
- |<------- relative deadline ------>|
- |<-------------- period ------------------->|
-.fi
-.in
-
-When setting a
-.B SCHED_DEADLINE
-policy for a thread using
-.BR sched_setattr (2),
-one can specify three parameters:
-.IR Runtime ,
-.IR Deadline ,
-and
-.IR Period .
-These parameters do not necessarily correspond to the aforementioned terms:
-usual practice is to set Runtime to something bigger than the average
-computation time (or worst-case execution time for hard real-time tasks),
-Deadline to the relative deadline, and Period to the period of the task.
-Thus, for
-.BR SCHED_DEADLINE
-scheduling, we have:
-
-.in +4n
-.nf
-arrival/wakeup absolute deadline
- | start time |
- | | |
- v v v
------x--------xooooooooooooooooo--------x--------x---
- |<-- Runtime ------->|
- |<----------- Deadline ----------->|
- |<-------------- Period ------------------->|
-.fi
-.in
-
-The three deadline-scheduling parameters correspond to the
-.IR sched_runtime ,
-.IR sched_deadline ,
-and
-.IR sched_period
-fields of the
-.I sched_attr
-structure; see
-.BR sched_setattr (2).
-These fields express value in nanoseconds.
-.\" FIXME It looks as though specifying sched_period as 0 means
-.\" "make sched_period the same as sched_deadline".
-.\" This needs to be documented.
-If
-.IR sched_period
-is specified as 0, then it is made the same as
-.IR sched_deadline .
-
-The kernel requires that:
-
- sched_runtime <= sched_deadline <= sched_period
-
-.\" See __checkparam_dl in kernel/sched/core.c
-In addition, under the current implementation,
-all of the parameter values must be at least 1024
-(i.e., just over one microsecond,
-which is the resolution of the implementation), and less than 2^63.
-If any of these checks fails,
-.BR sched_setattr (2)
-fails with the error
-.BR EINVAL .
-
-The CBS guarantees non-interference between tasks, by throttling
-threads that attempt to over-run their specified Runtime.
-
-To ensure deadline scheduling guarantees,
-the kernel must prevent situations where the set of
-.B SCHED_DEADLINE
-threads is not feasible (schedulable) within the given constraints.
-The kernel thus performs an admittance test when setting or changing
-.B SCHED_DEADLINE
-policy and attributes.
-This admission test calculates whether the change is feasible;
-if it is not
-.BR sched_setattr (2)
-fails with the error
-.BR EBUSY .
-
-For example, it is required (but not necessarily sufficient) for
-the total utilization to be less than or equal to the total number of
-CPUs available, where, since each thread can maximally run for
-Runtime per Period, that thread's utilization is its
-Runtime divided by its Period.
-
-In order to fulfil the guarantees that are made when
-a thread is admitted to the
-.BR SCHED_DEADLINE
-policy,
-.BR SCHED_DEADLINE
-threads are the highest priority (user controllable) threads in the
-system; if any
-.BR SCHED_DEADLINE
-thread is runnable,
-it will preempt any thread scheduled under one of the other policies.
-
-A call to
-.BR fork (2)
-by a thread scheduled under the
-.B SCHED_DEADLINE
-policy will fail with the error
-.BR EAGAIN ,
-unless the thread has its reset-on-fork flag set (see below).
-
-A
-.B SCHED_DEADLINE
-thread that calls
-.BR sched_yield (2)
-will yield the current job and wait for a new period to begin.
-.\"
-.\" FIXME Calling sched_getparam() on a SCHED_DEADLINE thread
-.\" fails with EINVAL, but sched_getscheduler() succeeds.
-.\" Is that intended? (Why?)
-.\"
-.SS SCHED_OTHER: Default Linux time-sharing scheduling
-\fBSCHED_OTHER\fP can be used at only static priority 0.
-\fBSCHED_OTHER\fP is the standard Linux time-sharing scheduler that is
-intended for all threads that do not require the special
-real-time mechanisms.
-The thread to run is chosen from the static
-priority 0 list based on a \fIdynamic\fP priority that is determined only
-inside this list.
-The dynamic priority is based on the nice value (set by
-.BR nice (2),
-.BR setpriority (2),
-or
-.BR sched_setattr (2))
-and increased for each time quantum the thread is ready to run,
-but denied to run by the scheduler.
-This ensures fair progress among all \fBSCHED_OTHER\fP threads.
-.\"
-.SS SCHED_BATCH: Scheduling batch processes
-(Since Linux 2.6.16.)
-\fBSCHED_BATCH\fP can be used only at static priority 0.
-This policy is similar to \fBSCHED_OTHER\fP in that it schedules
-the thread according to its dynamic priority
-(based on the nice value).
-The difference is that this policy
-will cause the scheduler to always assume
-that the thread is CPU-intensive.
-Consequently, the scheduler will apply a small scheduling
-penalty with respect to wakeup behavior,
-so that this thread is mildly disfavored in scheduling decisions.
-
-.\" The following paragraph is drawn largely from the text that
-.\" accompanied Ingo Molnar's patch for the implementation of
-.\" SCHED_BATCH.
-.\" commit b0a9499c3dd50d333e2aedb7e894873c58da3785
-This policy is useful for workloads that are noninteractive,
-but do not want to lower their nice value,
-and for workloads that want a deterministic scheduling policy without
-interactivity causing extra preemptions (between the workload's tasks).
-.\"
-.SS SCHED_IDLE: Scheduling very low priority jobs
-(Since Linux 2.6.23.)
-\fBSCHED_IDLE\fP can be used only at static priority 0;
-the process nice value has no influence for this policy.
-
-This policy is intended for running jobs at extremely low
-priority (lower even than a +19 nice value with the
-.B SCHED_OTHER
-or
-.B SCHED_BATCH
-policies).
-.\"
-.SS Resetting scheduling policy for child processes
-Each thread has a reset-on-fork scheduling flag.
-When this flag is set, children created by
-.BR fork (2)
-do not inherit privileged scheduling policies.
-The reset-on-fork flag can be set by either:
-.IP * 3
-ORing the
-.B SCHED_RESET_ON_FORK
-flag into the
-.I policy
-argument when calling
-.BR sched_setscheduler (2)
-(since Linux 2.6.32);
-or
-.IP *
-specifying the
-.B SCHED_FLAG_RESET_ON_FORK
-flag in
-.IR attr.sched_flags
-when calling
-.BR sched_setattr (2).
-.PP
-Note that the constants used with these two APIs have different names.
-The state of the reset-on-fork flag can analogously be retrieved using
-.BR sched_getscheduler (2)
-and
-.BR sched_getattr (2).
-
-The reset-on-fork feature is intended for media-playback applications,
-and can be used to prevent applications evading the
-.BR RLIMIT_RTTIME
-resource limit (see
-.BR getrlimit (2))
-by creating multiple child processes.
-
-More precisely, if the reset-on-fork flag is set,
-the following rules apply for subsequently created children:
-.IP * 3
-If the calling thread has a scheduling policy of
-.B SCHED_FIFO
-or
-.BR SCHED_RR ,
-the policy is reset to
-.BR SCHED_OTHER
-in child processes.
-.IP *
-If the calling process has a negative nice value,
-the nice value is reset to zero in child processes.
-.PP
-After the reset-on-fork flag has been enabled,
-it can be reset only if the thread has the
-.BR CAP_SYS_NICE
-capability.
-This flag is disabled in child processes created by
-.BR fork (2).
-.\"
-.SS Privileges and resource limits
-In Linux kernels before 2.6.12, only privileged
-.RB ( CAP_SYS_NICE )
-threads can set a nonzero static priority (i.e., set a real-time
-scheduling policy).
-The only change that an unprivileged thread can make is to set the
-.B SCHED_OTHER
-policy, and this can be done only if the effective user ID of the caller
-matches the real or effective user ID of the target thread
-(i.e., the thread specified by
-.IR pid )
-whose policy is being changed.
-
-A thread must be privileged
-.RB ( CAP_SYS_NICE )
-in order to set or modify a
-.BR SCHED_DEADLINE
-policy.
-
-Since Linux 2.6.12, the
-.B RLIMIT_RTPRIO
-resource limit defines a ceiling on an unprivileged thread's
-static priority for the
-.B SCHED_RR
-and
-.B SCHED_FIFO
-policies.
-The rules for changing scheduling policy and priority are as follows:
-.IP * 3
-If an unprivileged thread has a nonzero
-.B RLIMIT_RTPRIO
-soft limit, then it can change its scheduling policy and priority,
-subject to the restriction that the priority cannot be set to a
-value higher than the maximum of its current priority and its
-.B RLIMIT_RTPRIO
-soft limit.
-.IP *
-If the
-.B RLIMIT_RTPRIO
-soft limit is 0, then the only permitted changes are to lower the priority,
-or to switch to a non-real-time policy.
-.IP *
-Subject to the same rules,
-another unprivileged thread can also make these changes,
-as long as the effective user ID of the thread making the change
-matches the real or effective user ID of the target thread.
-.IP *
-Special rules apply for the
-.BR SCHED_IDLE
-policy.
-In Linux kernels before 2.6.39,
-an unprivileged thread operating under this policy cannot
-change its policy, regardless of the value of its
-.BR RLIMIT_RTPRIO
-resource limit.
-In Linux kernels since 2.6.39,
-.\" commit c02aa73b1d18e43cfd79c2f193b225e84ca497c8
-an unprivileged thread can switch to either the
-.BR SCHED_BATCH
-or the
-.BR SCHED_NORMAL
-policy so long as its nice value falls within the range permitted by its
-.BR RLIMIT_NICE
-resource limit (see
-.BR getrlimit (2)).
-.PP
-Privileged
-.RB ( CAP_SYS_NICE )
-threads ignore the
-.B RLIMIT_RTPRIO
-limit; as with older kernels,
-they can make arbitrary changes to scheduling policy and priority.
-See
-.BR getrlimit (2)
-for further information on
-.BR RLIMIT_RTPRIO .
-.SS Limiting the CPU usage of real-time and deadline processes
-A nonblocking infinite loop in a thread scheduled under the
-.BR SCHED_FIFO ,
-.BR SCHED_RR ,
-or
-.BR SCHED_DEADLINE
-policy will block all threads with lower
-priority forever.
-Prior to Linux 2.6.25, the only way of preventing a runaway real-time
-process from freezing the system was to run (at the console)
-a shell scheduled under a higher static priority than the tested application.
-This allows an emergency kill of tested
-real-time applications that do not block or terminate as expected.
-
-Since Linux 2.6.25, there are other techniques for dealing with runaway
-real-time and deadline processes.
-One of these is to use the
-.BR RLIMIT_RTTIME
-resource limit to set a ceiling on the CPU time that
-a real-time process may consume.
-See
-.BR getrlimit (2)
-for details.
-
-Since version 2.6.25, Linux also provides two
-.I /proc
-files that can be used to reserve a certain amount of CPU time
-to be used by non-real-time processes.
-Reserving some CPU time in this fashion allows some CPU time to be
-allocated to (say) a root shell that can be used to kill a runaway process.
-Both of these files specify time values in microseconds:
-.TP
-.IR /proc/sys/kernel/sched_rt_period_us
-This file specifies a scheduling period that is equivalent to
-100% CPU bandwidth.
-The value in this file can range from 1 to
-.BR INT_MAX ,
-giving an operating range of 1 microsecond to around 35 minutes.
-The default value in this file is 1,000,000 (1 second).
-.TP
-.IR /proc/sys/kernel/sched_rt_runtime_us
-The value in this file specifies how much of the "period" time
-can be used by all real-time and deadline scheduled processes
-on the system.
-The value in this file can range from \-1 to
-.BR INT_MAX \-1.
-Specifying \-1 makes the runtime the same as the period;
-that is, no CPU time is set aside for non-real-time processes
-(which was the Linux behavior before kernel 2.6.25).
-The default value in this file is 950,000 (0.95 seconds),
-meaning that 5% of the CPU time is reserved for processes that
-don't run under a real-time or deadline scheduling policy.
-.PP
-.SS Response time
-A blocked high priority thread waiting for I/O has a certain
-response time before it is scheduled again.
-The device driver writer
-can greatly reduce this response time by using a "slow interrupt"
-interrupt handler.
-.\" as described in
-.\" .BR request_irq (9).
-.SS Miscellaneous
-Child processes inherit the scheduling policy and parameters across a
-.BR fork (2).
-The scheduling policy and parameters are preserved across
-.BR execve (2).
-
-Memory locking is usually needed for real-time processes to avoid
-paging delays; this can be done with
-.BR mlock (2)
-or
-.BR mlockall (2).
-.SH NOTES
-.PP
-Originally, Standard Linux was intended as a general-purpose operating
-system being able to handle background processes, interactive
-applications, and less demanding real-time applications (applications that
-need to usually meet timing deadlines).
-Although the Linux kernel 2.6
-allowed for kernel preemption and the newly introduced O(1) scheduler
-ensures that the time needed to schedule is fixed and deterministic
-irrespective of the number of active tasks, true real-time computing
-was not possible up to kernel version 2.6.17.
-.SS Real-time features in the mainline Linux kernel
-.\" FIXME . Probably this text will need some minor tweaking
-.\" by about the time of 2.6.30; ask Carsten Emde about this then.
-From kernel version 2.6.18 onward, however, Linux is gradually
-becoming equipped with real-time capabilities,
-most of which are derived from the former
-.I realtime-preempt
-patches developed by Ingo Molnar, Thomas Gleixner,
-Steven Rostedt, and others.
-Until the patches have been completely merged into the
-mainline kernel
-(this is expected to be around kernel version 2.6.30),
-they must be installed to achieve the best real-time performance.
-These patches are named:
-.in +4n
-.nf
-
-patch-\fIkernelversion\fP-rt\fIpatchversion\fP
-.fi
-.in
-.PP
-and can be downloaded from
-.UR http://www.kernel.org\:/pub\:/linux\:/kernel\:/projects\:/rt/
-.UE .
-
-Without the patches and prior to their full inclusion into the mainline
-kernel, the kernel configuration offers only the three preemption classes
-.BR CONFIG_PREEMPT_NONE ,
-.BR CONFIG_PREEMPT_VOLUNTARY ,
-and
-.B CONFIG_PREEMPT_DESKTOP
-which respectively provide no, some, and considerable
-reduction of the worst-case scheduling latency.
-
-With the patches applied or after their full inclusion into the mainline
-kernel, the additional configuration item
-.B CONFIG_PREEMPT_RT
-becomes available.
-If this is selected, Linux is transformed into a regular
-real-time operating system.
-The FIFO and RR scheduling policies are then used to run a thread
-with true real-time priority and a minimum worst-case scheduling latency.
-.SH SEE ALSO
-.ad l
-.nh
-.BR chrt (1),
-.BR taskset (1),
-.BR getpriority (2),
-.BR mlock (2),
-.BR mlockall (2),
-.BR munlock (2),
-.BR munlockall (2),
-.BR nice (2),
-.BR sched_get_priority_max (2),
-.BR sched_get_priority_min (2),
-.BR sched_getscheduler (2),
-.BR sched_getaffinity (2),
-.BR sched_getparam (2),
-.BR sched_rr_get_interval (2),
-.BR sched_setaffinity (2),
-.BR sched_setscheduler (2),
-.BR sched_setparam (2),
-.BR sched_yield (2),
-.BR setpriority (2),
-.BR pthread_getaffinity_np (3),
-.BR pthread_setaffinity_np (3),
-.BR sched_getcpu (3),
-.BR capabilities (7),
-.BR cpuset (7)
-.ad
-.PP
-.I Programming for the real world \- POSIX.4
-by Bill O. Gallmeister, O'Reilly & Associates, Inc., ISBN 1-56592-074-0.
-.PP
-The Linux kernel source files
-.IR Documentation/scheduler/sched-deadline.txt ,
-.IR Documentation/scheduler/sched-rt-group.txt ,
-.IR Documentation/scheduler/sched-design-CFS.txt ,
-and
-.IR Documentation/scheduler/sched-nice-design.txt
-.SH COLOPHON
-This page is part of release 3.79 of the Linux
-.I man-pages
-project.
-A description of the project,
-information about reporting bugs,
-and the latest version of this page,
-can be found at
-\%http://www.kernel.org/doc/man\-pages/.
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