127 lines
3.6 KiB
Groff
127 lines
3.6 KiB
Groff
.\" $NetBSD: affinity.3,v 1.4 2009/01/20 01:57:36 rmind Exp $
|
|
.\"
|
|
.\" Copyright (c) 2008 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to The NetBSD Foundation
|
|
.\" by Mindaugas Rasiukevicius <rmind at NetBSD org>.
|
|
.\"
|
|
.\" 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.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
|
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
|
|
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
.\" POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.Dd October 18, 2008
|
|
.Dt AFFINITY 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm pthread_setaffinity_np ,
|
|
.Nm pthread_getaffinity_np
|
|
.Nd affinity of threads
|
|
.Sh LIBRARY
|
|
.Lb libpthread
|
|
.Sh SYNOPSIS
|
|
.In pthread.h
|
|
.In sched.h
|
|
.Ft int
|
|
.Fn pthread_setaffinity_np "pthread_t thread" "size_t size" "cpuset_t *set"
|
|
.Ft int
|
|
.Fn pthread_getaffinity_np "pthread_t thread" "size_t size" "cpuset_t *set"
|
|
.Sh DESCRIPTION
|
|
Thread affinity allows to run the thread on specified CPU or CPUs only.
|
|
.Pp
|
|
.Fn pthread_setaffinity_np
|
|
function sets the affinity mask
|
|
.Fa set
|
|
for
|
|
.Fa thread .
|
|
At least one valid CPU must be set in the mask.
|
|
.Pp
|
|
The
|
|
.Fn pthread_getaffinity_np
|
|
function gets the affinity mask of
|
|
.Fa thread
|
|
into
|
|
.Fa set .
|
|
.Pp
|
|
Note that
|
|
.Fa set
|
|
must be created and initialized using the
|
|
.Xr cpuset 3
|
|
functions.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn pthread_setaffinity_np
|
|
and
|
|
.Fn pthread_getaffinity_np
|
|
functions return 0 on success.
|
|
Otherwise, an error number is returned to indicate the error.
|
|
.Sh EXAMPLES
|
|
An example of code fragment, which sets the affinity for the current
|
|
thread to the CPU whose ID is 0:
|
|
.Bd -literal
|
|
cpuset_t *cset;
|
|
pthread_t pth;
|
|
cpuid_t ci;
|
|
|
|
cset = cpuset_create();
|
|
if (cset == NULL) {
|
|
err(EXIT_FAILURE, "cpuset_create");
|
|
}
|
|
ci = 0;
|
|
cpuset_set(ci, cset);
|
|
|
|
pth = pthread_self();
|
|
error = pthread_setaffinity_np(pth, cpuset_size(cset), cset);
|
|
if (error) {
|
|
...
|
|
}
|
|
cpuset_destroy(cset);
|
|
.Ed
|
|
.Sh ERRORS
|
|
The
|
|
.Fn pthread_setaffinity_np
|
|
and
|
|
.Fn pthread_getaffinity_np
|
|
functions fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The specified
|
|
.Fa set
|
|
was invalid.
|
|
.It Bq Er EPERM
|
|
The calling process lacks the appropriate privileges to perform
|
|
the operation.
|
|
.It Bq Er ESRCH
|
|
No thread could be found corresponding to the one specified by
|
|
.Fa thread .
|
|
.El
|
|
.Sh NOTES
|
|
There is an alternative processor sets interface, see
|
|
.Xr pset 3 .
|
|
However, thread affinity and processor sets are mutually exclusive,
|
|
hence mixing of these interfaces is prohibited.
|
|
.Sh SEE ALSO
|
|
.Xr cpuset 3 ,
|
|
.Xr pset 3 ,
|
|
.Xr pthread_getschedparam 3 ,
|
|
.Xr pthread_setschedparam 3 ,
|
|
.Xr sched 3 ,
|
|
.Xr schedctl 8
|