2008-11-05 01:52:21 +00:00
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.\" Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk
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.\" <mtk.manpages@gmail.com>
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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accept.2, clone.2, dup.2, fallocate.2, pipe.2, readahead.2, sched_setaffinity.2, unshare.2, CPU_SET.3, endian.3, euidaccess.3, fexecve.3, getpt.3, getpw.3, getumask.3, getutmp.3, gnu_get_libc_version.3, makedev.3, matherr.3, mbsnrtowcs.3, memfrob.3, pthread_attr_setaffinity_np.3, pthread_getattr_np.3, pthread_setaffinity_np.3, pthread_tryjoin_np.3, tcgetsid.3, wcscasecmp.3, wcsncasecmp.3, wcsnlen.3, wcsnrtombs.3, wcswidth.3, rtld-audit.7: SYNOPSIS: Add reference to feature_test_macros(7)
These pages specify feature test macros in the function
prototypes. Add a reference to feature_test_macros(7),
so that readers are pointed to the information that
feature test macros must be defined before including
*any* header file.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-10 05:06:22 +00:00
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.TH PTHREAD_SETAFFINITY_NP 3 2010-09-10 "Linux" "Linux Programmer's Manual"
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2008-11-05 01:52:21 +00:00
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.SH NAME
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pthread_setaffinity_np, pthread_getaffinity_np \- set/get
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CPU affinity of a thread
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.SH SYNOPSIS
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.nf
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accept.2, clone.2, dup.2, fallocate.2, pipe.2, readahead.2, sched_setaffinity.2, unshare.2, CPU_SET.3, endian.3, euidaccess.3, fexecve.3, getpt.3, getpw.3, getumask.3, getutmp.3, gnu_get_libc_version.3, makedev.3, matherr.3, mbsnrtowcs.3, memfrob.3, pthread_attr_setaffinity_np.3, pthread_getattr_np.3, pthread_setaffinity_np.3, pthread_tryjoin_np.3, tcgetsid.3, wcscasecmp.3, wcsncasecmp.3, wcsnlen.3, wcsnrtombs.3, wcswidth.3, rtld-audit.7: SYNOPSIS: Add reference to feature_test_macros(7)
These pages specify feature test macros in the function
prototypes. Add a reference to feature_test_macros(7),
so that readers are pointed to the information that
feature test macros must be defined before including
*any* header file.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-10 05:06:22 +00:00
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.BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"
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2008-11-05 01:52:21 +00:00
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.B #include <pthread.h>
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.BI "int pthread_setaffinity_np(pthread_t " thread ", size_t " cpusetsize ,
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.BI " const cpu_set_t *" cpuset );
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.BI "int pthread_getaffinity_np(pthread_t " thread ", size_t " cpusetsize ,
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.BI " cpu_set_t *" cpuset );
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.sp
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Compile and link with \fI\-pthread\fP.
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.SH DESCRIPTION
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The
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.BR pthread_setaffinity_np ()
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2009-09-27 06:58:35 +00:00
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function
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2008-11-05 01:52:21 +00:00
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sets the CPU affinity mask of the thread
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.I thread
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to the CPU set pointed to by
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.IR cpuset .
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If the call is successful,
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and the thread is not currently running on one of the CPUs in
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.IR cpuset ,
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then it is migrated to one of those CPUs.
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The
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.BR pthread_getaffinity_np ()
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function returns the CPU affinity mask of the thread
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.I thread
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in the buffer pointed to by
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.IR cpuset .
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2008-11-14 15:01:23 +00:00
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For more details on CPU affinity masks, see
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.BR sched_setaffinity (2).
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For a description of a set of macros
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that can be used to manipulate and inspect CPU sets, see
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.BR CPU_SET (3).
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2008-11-05 01:52:21 +00:00
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The argument
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.I cpusetsize
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is the length (in bytes) of the buffer pointed to by
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.IR cpuset .
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2008-11-12 18:50:51 +00:00
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Typically, this argument would be specified as
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2008-11-05 01:52:21 +00:00
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.IR sizeof(cpu_set_t) .
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2008-11-14 15:01:23 +00:00
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(It may be some other value, if using the macros described in
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.BR CPU_SET (3)
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for dynamically allocating a CPU set.)
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2008-11-05 01:52:21 +00:00
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.SH RETURN VALUE
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On success, these functions return 0;
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intro.1, time.1, adjtimex.2, capget.2, eventfd.2, fcntl.2, getrlimit.2, getsockopt.2, gettimeofday.2, intro.2, ioctl_list.2, ioperm.2, mlock.2, pivot_root.2, poll.2, prctl.2, ptrace.2, sched_setscheduler.2, select_tut.2, semget.2, sigaltstack.2, signalfd.2, sysctl.2, timer_settime.2, timerfd_create.2, wait.2, CPU_SET.3, argz_add.3, assert_perror.3, atexit.3, backtrace.3, bcmp.3, clearenv.3, ctime.3, dl_iterate_phdr.3, dlopen.3, ecvt.3, errno.3, error.3, ether_aton.3, exit.3, fenv.3, ferror.3, finite.3, flockfile.3, fnmatch.3, fpathconf.3, fpclassify.3, ftime.3, ftok.3, ftw.3, fwide.3, getaddrinfo.3, gethostbyname.3, getlogin.3, getnameinfo.3, getnetent.3, getopt.3, getprotoent.3, getrpcent.3, getservent.3, glob.3, hsearch.3, inet.3, isalpha.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, longjmp.3, lsearch.3, malloc.3, matherr.3, mblen.3, mbsinit.3, mbtowc.3, on_exit.3, printf.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_equal.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setschedparam.3, pthread_setschedprio.3, ptsname.3, putenv.3, putgrent.3, raise.3, rcmd.3, regex.3, rexec.3, rpc.3, rpmatch.3, rtnetlink.3, scandir.3, sem_init.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, signbit.3, stdio_ext.3, strtod.3, strtol.3, strtoul.3, system.3, termios.3, timeradd.3, tzset.3, ualarm.3, wctomb.3, xdr.3, st.4, tty_ioctl.4, core.5, elf.5, proc.5, bootparam.7, capabilities.7, icmp.7, ip.7, ipv6.7, math_error.7, mdoc.samples.7, mq_overview.7, pthreads.7, raw.7, regex.7, socket.7, tcp.7, tzselect.8: Global fix: s/non-zero/nonzero/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:40:55 +00:00
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on error, they return a nonzero error number.
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2008-11-05 01:52:21 +00:00
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.SH ERRORS
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.TP
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.B EFAULT
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A supplied memory address was invalid.
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.TP
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.B EINVAL
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.RB ( pthread_setaffinity_np ())
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The affinity bit mask
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.I mask
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2008-11-14 15:47:54 +00:00
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contains no processors that are currently physically on the system
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and permitted to the thread according to any restrictions that
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may be imposed by the "cpuset" mechanism described in
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.BR cpuset (7).
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2008-11-05 01:52:21 +00:00
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.TP
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.BR EINVAL
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.RB ( pthread_setaffinity_np ())
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.I cpuset
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2008-11-14 15:01:23 +00:00
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specified a CPU that was outside the set supported by the kernel.
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(The kernel configuration option
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.BR CONFIG_NR_CPUS
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2008-11-17 17:14:17 +00:00
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.\" FIXME . ?
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.\" Loic Domaigne commented: it seems that in the future the
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2010-10-15 06:29:41 +00:00
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.\" kernel developers want to make cpumask_t dynamic, so
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2008-11-17 17:14:17 +00:00
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.\" CONFIG_NR_CPUS might become obsolete in the future.
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2008-11-14 15:01:23 +00:00
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defines the range of the set supported by the kernel data type
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2008-11-05 01:52:21 +00:00
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.\" cpumask_t
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2008-11-14 15:01:23 +00:00
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used to represent CPU sets.)
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2008-11-05 01:52:21 +00:00
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.\" The raw sched_getaffinity() system call returns the size (in bytes)
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.\" of the cpumask_t type.
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.TP
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.B EINVAL
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2008-11-05 03:51:13 +00:00
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.RB ( pthread_getaffinity_np ())
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2008-11-05 01:52:21 +00:00
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.I cpusetsize
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is smaller than the size of the affinity mask used by the kernel.
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.TP
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.B ESRCH
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2008-11-17 18:01:42 +00:00
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No thread with the ID
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.I thread
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could be found.
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2008-11-05 01:52:21 +00:00
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.SH VERSIONS
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These functions are provided by glibc since version 2.3.4.
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.SH CONFORMING TO
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accept.2, execve.2, futimesat.2, getresuid.2, getrlimit.2, madvise.2, mq_getsetattr.2, msgctl.2, nice.2, open.2, poll.2, setresuid.2, shmctl.2, sigaction.2, times.2, utimensat.2, __setfpucw.3, atoi.3, endian.3, err.3, euidaccess.3, fenv.3, fopencookie.3, fpurge.3, getgrouplist.3, getutmp.3, j0.3, lgamma.3, netlink.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_cleanup_push_defer_np.3, pthread_getattr_np.3, pthread_kill_other_threads_np.3, pthread_setaffinity_np.3, pthread_tryjoin_np.3, pthread_yield.3, random_r.3, readdir.3, rtnetlink.3, scanf.3, setenv.3, significand.3, sigsetops.3, strerror.3, strstr.3, sysv_signal.3, termios.3, timegm.3, unlocked_stdio.3, y0.3, locale.5, bootparam.7, feature_test_macros.7, ip.7, locale.7, pthreads.7, rtld-audit.7, nscd.8: Global fix: s/non-standard/nonstandard/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:37:52 +00:00
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These functions are nonstandard GNU extensions;
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execve.2, fallocate.2, futex.2, sched_rr_get_interval.2, select_tut.2, shmget.2, timer_getoverrun.2, times.2, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_cleanup_push_defer_np.3, pthread_getattr_np.3, pthread_self.3, pthread_setaffinity_np.3, pthread_tryjoin_np.3, sem_open.3, stdin.3, rtc.4, tty_ioctl.4, unix.7: Global fix: s/non-portable/nonportable/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:46:09 +00:00
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hence the suffix "_np" (nonportable) in the names.
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2008-11-05 01:52:21 +00:00
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.SH NOTES
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2008-11-14 15:01:23 +00:00
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After a call to
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2008-11-14 15:08:46 +00:00
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.BR pthread_setaffinity_np (),
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2008-11-14 15:01:23 +00:00
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the set of CPUs on which the thread will actually run is
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the intersection of the set specified in the
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.I cpuset
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argument and the set of CPUs actually present on the system.
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The system may further restrict the set of CPUs on which the thread
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runs if the "cpuset" mechanism described in
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.BR cpuset (7)
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is being used.
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These restrictions on the actual set of CPUs on which the thread
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will run are silently imposed by the kernel.
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2008-11-05 01:52:21 +00:00
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These functions are implemented on top of the
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.BR sched_setaffinity (2)
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and
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.BR sched_getaffinity (2)
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system calls.
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In glibc 2.3.3 only,
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versions of these functions were provided that did not have a
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.I cpusetsize
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argument.
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Instead the CPU set size given to the underlying system calls was always
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.IR sizeof(cpu_set_t) .
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A new thread created by
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Changes, clone.2, mount.2, nanosleep.2, sigaltstack.2, statfs.2, timer_settime.2, ctime.3, fmemopen.3, nl_langinfo.3, posix_memalign.3, pthread_attr_init.3, pthread_setaffinity_np.3, pthread_setschedprio.3, pthread_testcancel.3, setjmp.3, sigwait.3, tty_ioctl.4, epoll.7, posixoptions.7, unix.7: Add section number to references to functions documented in other pages
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-11-01 07:07:28 +00:00
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.BR pthread_create (3)
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2008-11-05 01:52:21 +00:00
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inherits a copy of its creator's CPU affinity mask.
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.SH EXAMPLE
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In the following program, the main thread uses
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.BR pthread_setaffinity_np ()
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to set its CPU affinity mask to include CPUs 0 to 7
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(which may not all be available on the system),
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and then calls
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.BR pthread_getaffinity_np ()
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to check the resulting CPU affinity mask of the thread.
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.nf
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#define _GNU_SOURCE
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#include <pthread.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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2008-11-11 13:35:25 +00:00
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#define handle_error_en(en, msg) \\
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do { errno = en; perror(msg); exit(EXIT_FAILURE); } while (0)
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2008-11-05 01:52:21 +00:00
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int
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main(int argc, char *argv[])
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{
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int s, j;
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cpu_set_t cpuset;
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pthread_t thread;
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thread = pthread_self();
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/* Set affinity mask to include CPUs 0 to 7 */
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CPU_ZERO(&cpuset);
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for (j = 0; j < 8; j++)
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CPU_SET(j, &cpuset);
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s = pthread_setaffinity_np(thread, sizeof(cpu_set_t), &cpuset);
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if (s != 0)
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2008-11-11 13:35:25 +00:00
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handle_error_en(s, "pthread_setaffinity_np");
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2008-11-05 01:52:21 +00:00
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/* Check the actual affinity mask assigned to the thread */
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s = pthread_getaffinity_np(thread, sizeof(cpu_set_t), &cpuset);
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if (s != 0)
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2008-11-11 13:35:25 +00:00
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handle_error_en(s, "pthread_getaffinity_np");
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2008-11-05 01:52:21 +00:00
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printf("Set returned by pthread_getaffinity_np() contained:\\n");
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for (j = 0; j < CPU_SETSIZE; j++)
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if (CPU_ISSET(j, &cpuset))
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printf(" CPU %d\\n", j);
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exit(EXIT_SUCCESS);
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}
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.fi
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.SH SEE ALSO
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.BR sched_setaffinity (2),
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2008-11-05 02:15:55 +00:00
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.BR sched_setscheduler (2),
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.BR pthread_attr_setaffinity_np (3),
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2008-11-06 16:01:55 +00:00
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.BR pthread_self (3),
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clock_nanosleep.2, getpriority.2, kexec_load.2, nanosleep.2, nice.2, sched_setaffinity.2, timer_create.2, timer_delete.2, timer_settime.2, utime.2, btowc.3, futimes.3, log.3, pthread_attr_setguardsize.3, pthread_kill_other_threads_np.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setschedparam.3, pthread_setschedprio.3, pthread_tryjoin_np.3, strcoll.3, strcpy.3, string.3, strxfrm.3, networks.5, aio.7, sigevent.7, udplite.7: SEE ALSO: Place entries in correct order
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-11-01 05:34:26 +00:00
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.BR sched_getcpu (3),
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2008-11-05 01:52:21 +00:00
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.BR cpuset (7),
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.BR pthreads (7)
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