| sched_4bsd.4 (144831) | sched_4bsd.4 (147432) |
|---|---|
| 1.\" Copyright (c) 2005 Robert N. M. Watson 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 8 unchanged lines hidden (view full) --- 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" | 1.\" Copyright (c) 2005 Robert N. M. Watson 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 8 unchanged lines hidden (view full) --- 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" |
| 25.\" $FreeBSD: head/share/man/man4/sched_4bsd.4 144831 2005-04-09 08:47:38Z joel $ | 25.\" $FreeBSD: head/share/man/man4/sched_4bsd.4 147432 2005-06-16 18:46:17Z ru $ |
| 26.\" 27.Dd April 7, 2005 28.Os 29.Dt SCHED_4BSD 4 30.Sh NAME 31.Nm sched_4bsd | 26.\" 27.Dd April 7, 2005 28.Os 29.Dt SCHED_4BSD 4 30.Sh NAME 31.Nm sched_4bsd |
| 32.Nd 4.4BSD Scheduler | 32.Nd "4.4BSD scheduler" |
| 33.Sh SYNOPSIS 34.Cd "options SCHED_4BSD" 35.Sh DESCRIPTION | 33.Sh SYNOPSIS 34.Cd "options SCHED_4BSD" 35.Sh DESCRIPTION |
| 36The |
|
| 36.Nm | 37.Nm |
| 38scheduler |
|
| 37is the default system scheduler, providing both high throughput and solid 38interactive response in the presence of load. 39.Pp 40The following sysctls are relevant to the operation of 41.Nm : 42.Bl -tag -width indent | 39is the default system scheduler, providing both high throughput and solid 40interactive response in the presence of load. 41.Pp 42The following sysctls are relevant to the operation of 43.Nm : 44.Bl -tag -width indent |
| 43.It kern.sched.name | 45.It Va kern.sched.name |
| 44This read-only sysctl reports the name of the active scheduler. | 46This read-only sysctl reports the name of the active scheduler. |
| 45.It kern.sched.quantum | 47.It Va kern.sched.quantum |
| 46This read-write sysctl reports or sets the length of the quantum (in 47micro-seconds) granted to a thread. | 48This read-write sysctl reports or sets the length of the quantum (in 49micro-seconds) granted to a thread. |
| 48.It kern.sched.ipiwakeup.enabled | 50.It Va kern.sched.ipiwakeup.enabled |
| 49This read-write sysctl sets whether or not the scheduler will generate an 50inter-processor interrupt (IPI) to an idle CPU when a thread is woken up. 51Otherwise, idle CPUs will wait until the next clock tick before looking for 52new work. | 51This read-write sysctl sets whether or not the scheduler will generate an 52inter-processor interrupt (IPI) to an idle CPU when a thread is woken up. 53Otherwise, idle CPUs will wait until the next clock tick before looking for 54new work. |
| 53.It kern.sched.preemption | 55.It Va kern.sched.preemption |
| 54This read-only sysctl reports whether or not the kernel is configured to 55support preemption, which reduces the latency to run lower priority threads 56on wakeup. 57.El 58.Pp 59Some sysctls will be available only on systems supporting SMP. 60.Sh SEE ALSO 61.Xr sched_ule 4 , 62.Xr sysctl 8 63.Sh HISTORY 64The 65.Nm 66scheduler has been present, in various forms, since the inception of 67.Bx . 68.Sh BUGS 69While a highly robust and time-tested scheduler, 70.Nm 71lacks specific knowledge of how to schedule advantageously in non-symmetric 72processor configurations, such as hyper-threading. | 56This read-only sysctl reports whether or not the kernel is configured to 57support preemption, which reduces the latency to run lower priority threads 58on wakeup. 59.El 60.Pp 61Some sysctls will be available only on systems supporting SMP. 62.Sh SEE ALSO 63.Xr sched_ule 4 , 64.Xr sysctl 8 65.Sh HISTORY 66The 67.Nm 68scheduler has been present, in various forms, since the inception of 69.Bx . 70.Sh BUGS 71While a highly robust and time-tested scheduler, 72.Nm 73lacks specific knowledge of how to schedule advantageously in non-symmetric 74processor configurations, such as hyper-threading. |