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90 lines
2.8 KiB
Groff
90 lines
2.8 KiB
Groff
.\" Copyright (c) 2006 Xin LI
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd June 14, 2006
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.Os
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.Dt SCHED_CORE 4
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.Sh NAME
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.Nm sched_core
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.Nd CORE Scheduler
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.Sh SYNOPSIS
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.Cd "options SCHED_CORE"
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.Sh DESCRIPTION
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The
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.Nm
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scheduler
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is an experimental scheduler that provides a number of advanced scheduler
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features not present in
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.Xr sched_4bsd 4 ,
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the default system scheduler, nor
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.Xr sched_ule 4 where it is forked off.
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These features address SMP and interactivity and include:
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.Pp
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.Bl -bullet -compact -offset indent
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.It
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Nice value of timesharing processes is respected. Allocation of
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timeslice and interaction detection algorithm are based on
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nice value.
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.It
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Per-cpu scheduling queue and load balancing.
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.It
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O(1) scheduling.
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.It
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Some cpu affinity code in wakeup path.
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.It
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Support for POSIX SCHED_FIFO and SCHED_RR.
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.El
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.Pp
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The following sysctls are relevant to the operation of
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.Nm :
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.Bl -tag -width indent
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.It Va kern.sched.name
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This read-only sysctl reports the name of the active scheduler.
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.It Va kern.sched.imbalance_pct
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(SMP specific) Lower watermark that triggers thread migration
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if the differce is above this percentage.
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.It Va kern.sched.imbalance_pct2
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(SMP specific) Higher watermark where the current CPU is not
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considered the perferred one for migration.
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.El
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.Pp
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The
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.Nm
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scheduler
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is not enabled by default as it is experimental.
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.Sh SEE ALSO
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.Xr sched_4bsd 4 ,
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.Xr sched_ule 4 ,
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.Xr sysctl 8
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.Sh HISTORY
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The
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.Nm
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scheduler first appeared in
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.Fx 7.0 .
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.Sh AUTHORS
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.An David Xu
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.Aq davidxu@FreeBSD.org
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