+++ /dev/null
-.\" This man page is Copyright (C) 2006 Andi Kleen <ak@muc.de>.
-.\"
-.\" %%%LICENSE_START(VERBATIM_ONE_PARA)
-.\" Permission is granted to distribute possibly modified copies
-.\" of this page provided the header is included verbatim,
-.\" and in case of nontrivial modification author and date
-.\" of the modification is added to the header.
-.\" %%%LICENSE_END
-.\"
-.\" 2008, mtk, various edits
-.\"
-.TH GETCPU 2 2013-04-03 "Linux" "Linux Programmer's Manual"
-.SH NAME
-getcpu \- determine CPU and NUMA node on which the calling thread is running
-.SH SYNOPSIS
-.nf
-.B #include <linux/getcpu.h>
-.sp
-.BI "int getcpu(unsigned *" cpu ", unsigned *" node \
-", struct getcpu_cache *" tcache );
-.fi
-
-.IR Note :
-There is no glibc wrapper for this system call; see NOTES.
-.SH DESCRIPTION
-The
-.BR getcpu ()
-system call identifies the processor and node on which the calling
-thread or process is currently running and writes them into the
-integers pointed to by the
-.I cpu
-and
-.I node
-arguments.
-The processor is a unique small integer identifying a CPU.
-The node is a unique small identifier identifying a NUMA node.
-When either
-.I cpu
-or
-.I node
-is NULL nothing is written to the respective pointer.
-
-The third argument to this system call is nowadays unused,
-and should be specified as NULL
-unless portability to Linux 2.6.23 or earlier is required (see NOTES).
-
-The information placed in
-.I cpu
-is guaranteed to be current only at the time of the call:
-unless the CPU affinity has been fixed using
-.BR sched_setaffinity (2),
-the kernel might change the CPU at any time.
-(Normally this does not happen
-because the scheduler tries to minimize movements between CPUs to
-keep caches hot, but it is possible.)
-The caller must allow for the possibility that the information returned in
-.I cpu
-and
-.I node
-is no longer current by the time the call returns.
-.SH RETURN VALUE
-On success, 0 is returned.
-On error, \-1 is returned, and
-.I errno
-is set appropriately.
-.SH ERRORS
-.TP
-.B EFAULT
-Arguments point outside the calling process's address space.
-.SH VERSIONS
-.BR getcpu ()
-was added in kernel 2.6.19 for x86_64 and i386.
-.SH CONFORMING TO
-.BR getcpu ()
-is Linux-specific.
-.SH NOTES
-Linux makes a best effort to make this call as fast possible.
-The intention of
-.BR getcpu ()
-is to allow programs to make optimizations with per-CPU data
-or for NUMA optimization.
-
-Glibc does not provide a wrapper for this system call; call it using
-.BR syscall (2);
-or use
-.BR sched_getcpu (3)
-instead.
-
-The
-.I tcache
-argument is unused since Linux 2.6.24.
-.\" commit 4307d1e5ada595c87f9a4d16db16ba5edb70dcb1
-.\" Author: Ingo Molnar <mingo@elte.hu>
-.\" Date: Wed Nov 7 18:37:48 2007 +0100
-.\" x86: ignore the sys_getcpu() tcache parameter
-In earlier kernels,
-if this argument was non-NULL,
-then it specified a pointer to a caller-allocated buffer in thread-local
-storage that was used to provide a caching mechanism for
-.BR getcpu ().
-Use of the cache could speed
-.BR getcpu ()
-calls, at the cost that there was a very small chance that
-the returned information would be out of date.
-The caching mechanism was considered to cause problems when
-migrating threads between CPUs, and so the argument is now ignored.
-.\"
-.\" ===== Before kernel 2.6.24: =====
-.\" .I tcache
-.\" is a pointer to a
-.\" .IR "struct getcpu_cache"
-.\" that is used as a cache by
-.\" .BR getcpu ().
-.\" The caller should put the cache into a thread-local variable
-.\" if the process is multithreaded,
-.\" because the cache cannot be shared between different threads.
-.\" .I tcache
-.\" can be NULL.
-.\" If it is not NULL
-.\" .BR getcpu ()
-.\" will use it to speed up operation.
-.\" The information inside the cache is private to the system call
-.\" and should not be accessed by the user program.
-.\" The information placed in the cache can change between kernel releases.
-.\"
-.\" When no cache is specified
-.\" .BR getcpu ()
-.\" will be slower,
-.\" but always retrieve the current CPU and node information.
-.\" With a cache
-.\" .BR getcpu ()
-.\" is faster.
-.\" However, the cached information is updated only once per jiffy (see
-.\" .BR time (7)).
-.\" This means that the information could theoretically be out of date,
-.\" although in practice the scheduler's attempt to maintain
-.\" soft CPU affinity means that the information is unlikely to change
-.\" over the course of the caching interval.
-.SH SEE ALSO
-.BR mbind (2),
-.BR sched_setaffinity (2),
-.BR set_mempolicy (2),
-.BR sched_getcpu (3),
-.BR cpuset (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/.
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