157 lines
4.2 KiB
Groff
157 lines
4.2 KiB
Groff
.\"-
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.\" Copyright (c) 2010 Xin LI <delphij@FreeBSD.org>
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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 AUTHOR 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 AUTHOR 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 March 23, 2010
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.Dt PTHREAD_AFFINITY_NP 3
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.Os
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.Sh NAME
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.Nm pthread_getaffinity_np ,
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.Nm pthread_setaffinity_np
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.Nd manage CPU affinity
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.Sh LIBRARY
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.Lb libpthread
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.Sh SYNOPSIS
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.In pthread_np.h
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.Ft int
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.Fn pthread_getaffinity_np "pthread_t td" "size_t cpusetsize" "cpuset_t *cpusetp"
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.Ft int
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.Fn pthread_setaffinity_np "pthread_t td" "size_t cpusetsize" "const cpuset_t *cpusetp"
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.Sh DESCRIPTION
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.Fn pthread_getaffinity_np
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and
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.Fn pthread_setaffinity_np
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allow the manipulation of sets of CPUs available to the specified thread.
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.Pp
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Masks of type
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.Ft cpuset_t
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are composed using the
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.Xr CPU_SET 3
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macros.
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The kernel tolerates large sets as long as all CPUs specified
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in the set exist.
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Sets smaller than the kernel uses generate an error on calls to
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.Fn pthread_getaffinity_np
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even if the result set would fit within the user supplied set.
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Calls to
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.Fn pthread_setaffinity_np
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tolerate small sets with no restrictions.
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.Pp
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The supplied mask should have a size of
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.Fa cpusetsize
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bytes.
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This size is usually provided by calling
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.Li sizeof(cpuset_t)
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which is ultimately determined by the value of
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.Dv CPU_SETSIZE
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as defined in
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.In sys/cpuset.h .
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.Pp
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.Fn pthread_getaffinity_np
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retrieves the
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mask from the thread specified by
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.Fa td ,
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and stores it in the space provided by
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.Fa cpusetp .
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.Pp
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.Fn pthread_setaffinity_np
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attempts to set the mask for the thread specified by
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.Fa td
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to the value in
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.Fa cpusetp .
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.Sh RETURN VALUES
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If successful, the
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.Fn pthread_getaffinity_np
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and
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.Fn pthread_setaffinity_np
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functions will return zero.
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Otherwise an error number will be returned
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to indicate the error.
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.Sh ERRORS
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The
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.Fn pthread_getaffinity_np
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and
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.Fn pthread_setaffinity_np
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functions may fail if:
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.Bl -tag -width Er
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.It Bq Er EDEADLK
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The
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.Fn pthread_setaffinity_np
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call would leave a thread without a valid CPU to run on because the set
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does not overlap with the thread's anonymous mask.
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.It Bq Er EFAULT
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The
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.Fa cpusetp
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pointer passed was invalid.
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.It Bq Er ESRCH
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The thread specified by the
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.Fa td
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argument could not be found.
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.It Bq Er ERANGE
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The
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.Fa cpusetsize
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was either preposterously large or smaller than the kernel set size.
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.It Bq Er EPERM
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The calling thread did not have the credentials required to complete the
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operation.
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.El
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.Sh SEE ALSO
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.Xr cpuset 1 ,
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.Xr cpuset 2 ,
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.Xr cpuset_getid 2 ,
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.Xr cpuset_setid 2 ,
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.Xr CPU_SET 3 ,
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.Xr pthread 3 ,
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.Xr pthread_attr_getaffinity_np 3 ,
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.Xr pthread_attr_setaffinity_np 3
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.Sh STANDARDS
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The
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.Nm pthread_getaffinity_np
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and
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.Nm pthread_setaffinity_np
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functions are non-standard
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.Fx
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extensions and may be not available on other operating systems.
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.Sh HISTORY
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The
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.Nm pthread_getaffinity_np
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and
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.Nm pthread_setaffinity_np
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function first appeared in
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.Fx 7.2 .
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.Sh AUTHORS
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.An -nosplit
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The
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.Nm pthread_getaffinity_np
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and
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.Nm pthread_setaffinity_np
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functions were written by
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.An David Xu
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.Aq davidxu@FreeBSD.org ,
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and this manpage was written by
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.An Xin LI
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.Aq delphij@FreeBSD.org .
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