pthread_attr_setaffinity_np, pthread_attr_getaffinity_np — set/get CPU affinity of a thread
#define _GNU_SOURCE #include <pthread.h>
int
pthread_attr_setaffinity_np( |
pthread_attr_t | attr, |
size_t | cpusetsize, | |
const cpu_set_t * | cpuset) ; |
int
pthread_attr_getaffinity_np( |
pthread_attr_t | attr, |
size_t | cpusetsize, | |
cpu_set_t * | cpuset) ; |
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Note |
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Compile and link with |
The pthread_attr_setaffinity_np
() sets the CPU
affinity mask attribute of the thread attributes object
referred to by attr
to the value specified in cpuset
. This attribute
determines the CPU affinity mask of a thread created using
the thread attributes object attr
.
The pthread_attr_getaffinity_np
() returns the
CPU affinity mask attribute of the thread attributes object
referred to by attr
in the buffer pointed to by cpuset
.
The argument cpusetsize
is the length (in
bytes) of the buffer pointed to by cpuset
. Normally this argument
would be specified as sizeof(cpu_set_t)
. The
constant CPU_SETSIZE
specifies
a value one greater than the maximum CPU number that can be
stored in a CPU set.
For more details on CPU affinity masks, as well as a description of a set of macros that can be used to manipulate and inspect CPU sets, see sched_setaffinity(2) for details.
attr
or
cpuset
is
invalid.
(pthread_attr_setaffinity_np
())
cpuset
specified a CPU that was outside the range permitted by
the kernel data type used to represent CPU sets. This
range is determined by the kernel configuration option
CONFIG_NR_CPUS
.
(pthread_getaffinity_np
()) A CPU in
the affinity mask of the thread attributes object
referred to by attr
lies outside the
range specified by cpusetsize
.
(pthread_attr_setaffinity_np
()) Could
not allocate memory.
These functions are non-standard GNU extensions; hence the suffix "_np" (non-portable) in the names.
In glibc 2.3.3 only, versions of these functions were
provided that did not have a cpusetsize
argument. Instead
the CPU set size given to the underlying system calls was
always sizeof(cpu_set_t)
.
sched_setaffinity(2), sched_setscheduler(2), pthread_attr_init(3), pthread_setaffinity_np(3), cpuset(7), pthreads(7)
This page is part of release 3.12 of the Linux man-pages
project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man-pages/.
Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk <mtk.manpagesgmail.com> Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. |