.\"
.\" Copyright (c) 2012
.\"	The DragonFly Project.  All rights reserved.
.\" This code is derived from software contributed to The DragonFly Project
.\" by Matthew Dillon <dillon@backplane.com> and Thomas Nikolajsen
.\" <thomas.nikolajsen@mail.dk>
.\"
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.\" modification, are permitted provided that the following conditions
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.Dd October 21, 2012
.Dt USCHED 8
.Os
.Sh NAME
.Nm usched
.Nd run a program with a specified userland scheduler and cpumask
.Sh SYNOPSIS
.Nm
.Op Fl d
.Brq Ar scheduler Ns Oo Cm \&: Ns Ar cpumask Oc | Cm \&: Ns Ar cpumask
.Ar program
.Op Ar argument ...
.Sh DESCRIPTION
Run
.Ar program
using the specified userland
.Ar scheduler
on
.Tn CPUs
given in
.Ar cpumask .
It assigns the
.Ar program
to the
.Tn CPU
with the smallest cpuid and adds the rest of the
.Tn CPUs
to the list of available
.Tn CPUs
for the
.Ar program .
The userland
.Ar scheduler
can have value
.Sq bsd4
or
.Sq dfly .
If
.Ar scheduler
is not specified,
userland scheduler is inherited from parent process
.Pq Nm .
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl d
Add debug output.
.El
.Pp
.Nm
is only usable for super user as other users cannot change
userland scheduler or cpumask.
.Pp
System default userland scheduler can be changed in
.Xr loader.conf 5 ,
see
.Xr loader 8 .
.Sh EXIT STATUS
.Ex -std usched
.Sh EXAMPLES
Run
.Xr sh 1
using only first 3
.Tn CPUs .
.Pp
.Dl usched :7 sh
.Pp
Run
.Xr sh 1
using userland scheduler
.Sq bsd4
using only first 4
.Tn CPUs .
.Pp
.Dl usched bsd4:0xf sh
.Sh SEE ALSO
.Xr usched_set 2 ,
.Xr loader.conf 5 ,
.Xr loader 8
.Sh HISTORY
The
.Nm
utility first appeared in
.Dx 3.1 .
.Sh AUTHORS
.An Matthew Dillon Aq Mt dillon@backplane.com
.An Thomas Nikolajsen Aq Mt thomas.nikolajsen@mail.dk
.Sh BUGS
Using system default userland scheduler by specifying
.Ar scheduler
as
.Sq default
is not implemented.
.Pp
.Ar cpumask
only supports up to 64 CPUs due to implementation of usched.