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freebsd/share/man/man4/sched_core.4
2006-09-30 15:14:49 +00:00

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.Dd June 30, 2006
.Os
.Dt SCHED_CORE 4
.Sh NAME
.Nm sched_core
.Nd CORE scheduler
.Sh SYNOPSIS
.Cd "options SCHED_CORE"
.Sh DESCRIPTION
The
.Nm
scheduler
is an experimental scheduler that provides a number of advanced scheduler
features not present in
.Xr sched_4bsd 4 ,
the default system scheduler, nor
.Xr sched_ule 4
where it is forked off.
These features address SMP and interactivity and include:
.Pp
.Bl -bullet -compact -offset indent
.It
Nice value of timesharing processes is respected.
Allocation of
time slice and interaction detection algorithm are based on
nice value.
.It
Per-CPU scheduling queue and load balancing.
.It
O(1) scheduling.
.It
Some CPU affinity code in wakeup path.
.It
Some preliminary support for Hyper Threading Technology.
.It
Support for POSIX SCHED_FIFO and SCHED_RR.
.El
.Pp
The following sysctls are relevant to the operation of
.Nm :
.Bl -tag -width indent
.It Va kern.sched.name
This read-only sysctl reports the name of the active scheduler.
.It Va kern.sched.ipiwakeup.enabled
(SMP specific) Whether to allow forwarding of wakeup to idle CPUs.
.It Va kern.sched.ipiwakeup.requested
(SMP specific) Requests for forwarding of wakeup to idle CPUs,
read-only.
.It Va kern.sched.ipiwakeup.requested
(SMP specific) Completed forwarding of wakeup to idle CPUs,
read-only.
.It Va kern.sched.ipiwakeup.usemask
(SMP specific) Whether to use the mask of idle CPUs.
.It Va kern.sched.ipiwakeup.useloop
(SMP specific) Whether to use loop to find idle CPUs.
.It Va kern.sched.ipiwakeup.onecpu
(SMP specific) Whether to only signal one CPU when doing wakeup.
.It Va kern.sched.ipiwakeup.htt
(SMP specific) Whether to take Hyper-Threading into account.
.El
.Pp
The
.Nm
scheduler
is not enabled by default as it is experimental.
.Sh SEE ALSO
.Xr sched_4bsd 4 ,
.Xr sched_ule 4 ,
.Xr sysctl 8
.Sh HISTORY
The
.Nm
scheduler first appeared in
.Fx 7.0 .
.Sh AUTHORS
.An David Xu
.Aq davidxu@FreeBSD.org