+++ /dev/null
-.\" Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk
-.\" <mtk.manpages@gmail.com>
-.\"
-.\" %%%LICENSE_START(VERBATIM)
-.\" 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-.\" manual page may be incorrect or out-of-date.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.
-.\" %%%LICENSE_END
-.\"
-.TH PTHREAD_SETAFFINITY_NP 3 2014-05-23 "Linux" "Linux Programmer's Manual"
-.SH NAME
-pthread_setaffinity_np, pthread_getaffinity_np \- set/get
-CPU affinity of a thread
-.SH SYNOPSIS
-.nf
-.BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"
-.B #include <pthread.h>
-
-.BI "int pthread_setaffinity_np(pthread_t " thread ", size_t " cpusetsize ,
-.BI " const cpu_set_t *" cpuset );
-.BI "int pthread_getaffinity_np(pthread_t " thread ", size_t " cpusetsize ,
-.BI " cpu_set_t *" cpuset );
-.sp
-Compile and link with \fI\-pthread\fP.
-.fi
-.SH DESCRIPTION
-The
-.BR pthread_setaffinity_np ()
-function
-sets the CPU affinity mask of the thread
-.I thread
-to the CPU set pointed to by
-.IR cpuset .
-If the call is successful,
-and the thread is not currently running on one of the CPUs in
-.IR cpuset ,
-then it is migrated to one of those CPUs.
-
-The
-.BR pthread_getaffinity_np ()
-function returns the CPU affinity mask of the thread
-.I thread
-in the buffer pointed to by
-.IR cpuset .
-
-For more details on CPU affinity masks, see
-.BR sched_setaffinity (2).
-For a description of a set of macros
-that can be used to manipulate and inspect CPU sets, see
-.BR CPU_SET (3).
-
-The argument
-.I cpusetsize
-is the length (in bytes) of the buffer pointed to by
-.IR cpuset .
-Typically, this argument would be specified as
-.IR sizeof(cpu_set_t) .
-(It may be some other value, if using the macros described in
-.BR CPU_SET (3)
-for dynamically allocating a CPU set.)
-.SH RETURN VALUE
-On success, these functions return 0;
-on error, they return a nonzero error number.
-.SH ERRORS
-.TP
-.B EFAULT
-A supplied memory address was invalid.
-.TP
-.B EINVAL
-.RB ( pthread_setaffinity_np ())
-The affinity bit mask
-.I mask
-contains no processors that are currently physically on the system
-and permitted to the thread according to any restrictions that
-may be imposed by the "cpuset" mechanism described in
-.BR cpuset (7).
-.TP
-.BR EINVAL
-.RB ( pthread_setaffinity_np ())
-.I cpuset
-specified a CPU that was outside the set supported by the kernel.
-(The kernel configuration option
-.BR CONFIG_NR_CPUS
-.\" FIXME . ?
-.\" Loic Domaigne commented: it seems that in the future the
-.\" kernel developers want to make cpumask_t dynamic, so
-.\" CONFIG_NR_CPUS might become obsolete in the future.
-defines the range of the set supported by the kernel data type
-.\" cpumask_t
-used to represent CPU sets.)
-.\" The raw sched_getaffinity() system call returns the size (in bytes)
-.\" of the cpumask_t type.
-.TP
-.B EINVAL
-.RB ( pthread_getaffinity_np ())
-.I cpusetsize
-is smaller than the size of the affinity mask used by the kernel.
-.TP
-.B ESRCH
-No thread with the ID
-.I thread
-could be found.
-.SH VERSIONS
-These functions are provided by glibc since version 2.3.4.
-.SH ATTRIBUTES
-.SS Multithreading (see pthreads(7))
-The
-.BR pthread_setaffinity_np ()
-and
-.BR pthread_getaffinity_np ()
-functions are thread-safe.
-.SH CONFORMING TO
-These functions are nonstandard GNU extensions;
-hence the suffix "_np" (nonportable) in the names.
-.SH NOTES
-After a call to
-.BR pthread_setaffinity_np (),
-the set of CPUs on which the thread will actually run is
-the intersection of the set specified in the
-.I cpuset
-argument and the set of CPUs actually present on the system.
-The system may further restrict the set of CPUs on which the thread
-runs if the "cpuset" mechanism described in
-.BR cpuset (7)
-is being used.
-These restrictions on the actual set of CPUs on which the thread
-will run are silently imposed by the kernel.
-
-These functions are implemented on top of the
-.BR sched_setaffinity (2)
-and
-.BR sched_getaffinity (2)
-system calls.
-
-In glibc 2.3.3 only,
-versions of these functions were provided that did not have a
-.I cpusetsize
-argument.
-Instead the CPU set size given to the underlying system calls was always
-.IR sizeof(cpu_set_t) .
-
-A new thread created by
-.BR pthread_create (3)
-inherits a copy of its creator's CPU affinity mask.
-.SH EXAMPLE
-In the following program, the main thread uses
-.BR pthread_setaffinity_np ()
-to set its CPU affinity mask to include CPUs 0 to 7
-(which may not all be available on the system),
-and then calls
-.BR pthread_getaffinity_np ()
-to check the resulting CPU affinity mask of the thread.
-
-.nf
-#define _GNU_SOURCE
-#include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <errno.h>
-
-#define handle_error_en(en, msg) \\
- do { errno = en; perror(msg); exit(EXIT_FAILURE); } while (0)
-
-int
-main(int argc, char *argv[])
-{
- int s, j;
- cpu_set_t cpuset;
- pthread_t thread;
-
- thread = pthread_self();
-
- /* Set affinity mask to include CPUs 0 to 7 */
-
- CPU_ZERO(&cpuset);
- for (j = 0; j < 8; j++)
- CPU_SET(j, &cpuset);
-
- s = pthread_setaffinity_np(thread, sizeof(cpu_set_t), &cpuset);
- if (s != 0)
- handle_error_en(s, "pthread_setaffinity_np");
-
- /* Check the actual affinity mask assigned to the thread */
-
- s = pthread_getaffinity_np(thread, sizeof(cpu_set_t), &cpuset);
- if (s != 0)
- handle_error_en(s, "pthread_getaffinity_np");
-
- printf("Set returned by pthread_getaffinity_np() contained:\\n");
- for (j = 0; j < CPU_SETSIZE; j++)
- if (CPU_ISSET(j, &cpuset))
- printf(" CPU %d\\n", j);
-
- exit(EXIT_SUCCESS);
-}
-.fi
-.SH SEE ALSO
-.BR sched_setaffinity (2),
-.BR pthread_attr_setaffinity_np (3),
-.BR pthread_self (3),
-.BR sched_getcpu (3),
-.BR cpuset (7),
-.BR pthreads (7),
-.BR sched (7)
-.SH COLOPHON
-This page is part of release 3.79 of the Linux
-.I man-pages
-project.
-A description of the project,
-information about reporting bugs,
-and the latest version of this page,
-can be found at
-\%http://www.kernel.org/doc/man\-pages/.
OSDN Git Service
