Mon Jan 9 20:08:26 2017 UTC ()

Document kern.sched sysctl variables.


(hubertf)

diff -r1.107 -r1.108 src/share/man/man7/sysctl.7

--- src/share/man/man7/sysctl.7 2017/01/08 14:28:42	1.107
+++ src/share/man/man7/sysctl.7 2017/01/09 20:08:26	1.108

 @@ -1,14 +1,14 @@
-.\"	$NetBSD: sysctl.7,v 1.107 2017/01/08 14:28:42 wiz Exp $
+.\"	$NetBSD: sysctl.7,v 1.108 2017/01/09 20:08:26 hubertf Exp $
 .\"
 .\" Copyright (c) 1993
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
 .\" are met:
 .\" 1. Redistributions of source code must retain the above copyright
 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 .\"    documentation and/or other materials provided with the distribution.
 .\" 3. Neither the name of the University nor the names of its contributors
 @@ -345,27 +345,27 @@ privilege may change the value.
 .It kern.posix_threads	integer	no
 .It kern.posix_timers	integer	no
 .It kern.proc	struct kinfo_proc	no
 .It kern.proc2	struct kinfo_proc2	no
 .It kern.proc_args	string	no
 .It kern.profiling	node	not applicable
 .\".It kern.pset	node	not applicable
 .It kern.rawpartition	integer	no
 .It kern.root_device	string	no
 .It kern.root_partition	integer	no
 .It kern.rtc_offset	integer	yes
 .It kern.saved_ids	integer	no
 .It kern.sbmax	integer	yes
-.\".It kern.sched	node	not applicable
+.It kern.sched	node	not applicable
 .It kern.securelevel	integer	raise only
 .It kern.somaxkva	integer	yes
 .It kern.synchronized_io	integer	no
 .It kern.timecounter	node	not applicable
 .It kern.timex	struct	no
 .It kern.tkstat	node	not applicable
 .It kern.tty	node	not applicable
 .It kern.urandom	integer	no
 .It kern.usercrypto	integer	yes
 .It kern.userasymcrypto	integer	yes
 .It kern.veriexec	node	not applicable
 .It kern.version	string	no
 .It kern.vnode	struct vnode	no
 @@ -1047,28 +1047,124 @@ The name of the root device (e.g.,
 .Dq wd0 ) .
 .It Li kern.root_partition ( Dv KERN_ROOT_PARTITION )
 The root partition on the root device (a == 0).
 .It Li kern.rtc_offset ( Dv KERN_RTC_OFFSET )
 Return the offset of real time clock from UTC in minutes.
 .It Li kern.saved_ids ( Dv KERN_SAVED_IDS )
 Returns 1 if saved set-group and saved set-user ID is available.
 .It Li kern.sbmax ( Dv KERN_SBMAX )
 Maximum socket buffer size.
 .\" XXX units?
 .It Li kern.securelevel ( Dv KERN_SECURELVL )
 See
 .Xr secmodel_securelevel 9 .
-.\" .It Li kern.sched
+.It Li kern.sched ( dynamic )
-.\" XXX: Undocumented.
+Influence the scheduling of LWPs, their priorisation and how they are
 distributed on and moved between CPUs.
 .Bl -column "kern.sched.balance_period" "integer" "Changeable" -offset indent
 .It Sy Third level name	   Sy Type	 Sy Changeable
 .It kern.sched.cacheht_time	   integer	 yes
 .It kern.sched.balance_period	   integer	 yes
 .It kern.sched.average_weight	   integer	 yes
 .It kern.sched.min_catch	   integer	 yes
 .It kern.sched.timesoftints	   integer	 yes
 .It kern.sched.kpreempt_pri	   integer	 yes
 .It kern.sched.upreempt_pri	   integer	 yes
 .It kern.sched.maxts	   integer	 yes
 .It kern.sched.mints	   integer	 yes
 .It kern.sched.name	   string	 no
 .It kern.sched.rtts	   integer	 no
 .It kern.sched.pri_min	   integer	 no
 .It kern.sched.pri_max	   integer	 no
 .El
 .Pp
 The variables are as follows:
 .Bl -tag -width "123456"
 .It Li kern.sched.cacheht_time ( dynamic )
 Cache hotness time in which a LWP is kept on one particular CPU
 and not moved to another CPU. This reduces the overhead of flushing
 and reloading caches.
 Defaults to 3ms.
 Needs to be given in
 .Dq hz
 units, see
 .Xr mstohz 9 .
 .It Li kern.sched.balance_period ( dynamic )
 Interval at which the CPU queues are checked for re-balancing.
 Defaults to 300ms.
 Needs to be given in
 .Dq hz
 units, see
 .Xr mstohz 9 .
 .It Li kern.sched.average_weight ( dynamic )
 Can be used to influence how likely LWPs are to be migrated from
 one CPU's queue of LWPs that are ready to run to a different, idle CPU.
 The value gives the percentage for weighting the average count of
 migratable threads from the past against the current number of
 migratable threads.
 A small value gives more weight to the past, a larger values more weight
 on the current situation.
 Defaults to 50 and must be between 0 and 100.
 .It Li kern.sched.min_catch ( dynamic )
 Minimum count of migratable (runable) threads for catching (stealing)
 from another CPU.
 Defaults to 1 but can be increased to decrease chance of thread
 migration between CPUs.
 .It Li kern.sched.timesoftints ( dynamic )
 Enable tracking of CPU time for soft interrupts
 as part of a LWP's real execution time.
 Set to a non-zero value to enable,
 and see
 .Xr ps 1
 for printing CPU times.
 .It Li kern.sched.kpreempt_pri ( dynamic )
 Minimum priority to trigger kernel preemption.
 .It Li kern.sched.upreempt_pri ( dynamic )
 Minimum priority to trigger user preemption.
 .It Li kern.sched.maxts ( dynamic )
 Scheduler specific maximal time quantum (in milliseconds).
 Must be set to a value larger than
 .Dq mints
 and between 10 and
 .Dq hz
 as given by the
 .Dv kern.clockrate
 sysctl.
 Provided by the M2 scheduler.
 .It Li kern.sched.mints ( dynamic )
 Scheduler specific minimal time quantum (in milliseconds).
 Must be set to a value smaller than
 .Dq maxts
 and between 1 and
 .Dq hz
 as given by the
 .Dq kern.clockrate
 sysctl.
 Provided by the M2 scheduler.
 .It Li kern.sched.name ( dynamic )
 Scheduler name.
 Provided both by the M2 and the 4BSD scheduler.
 .It Li kern.sched.rtts ( dynamic )
 Fixed scheduler specific round-robin time quantum in milliseconds.
 Provided both by the M2 and the 4BSD scheduler.
 .It Li kern.sched.pri_min ( dynamic )
 Minimal POSIX real-time priority.
 See
 .Xr sched 3 .
 .It Li kern.sched.pri_max ( dynamic )
 Maximal POSIX real-time priority.
 See
 .Xr sched 3 .
 .El
 .It Li kern.somaxkva ( Dv KERN_SOMAXKVA )
 Maximum amount of kernel memory to be used for socket buffers.
 .\" XXX units?
 .It Li kern.synchronized_io ( Dv KERN_SYNCHRONIZED_IO )
 Returns 1 if the
 .St -p1003.1b-93
 Synchronized I/O Option is available on this system,
 otherwise\ 0.
 .It Li kern.timecounter ( dynamic )
 Display and control the timecounter source of the system.
 .Bl -column "kern.timecounter.timestepwarnings" "integer" "Changeable" -offset indent
 .It Sy Third level name Ta Sy Type Ta Sy Changeable
 .It kern.timecounter.choice	string	no