PTHREAD_CREATE(3) manual page

From b41f74438672dd682bc01ae818cb3da654f22c1e Mon Sep 17 00:00:00 2001 From: marha Date: Wed, 13 Feb 2013 10:41:10 +0100 Subject: Updated to latest CVS version of pthreads --- pthreads/manual/sched_setaffinity.html | 143 +++++++++++++++++++++++++++++++++ 1 file changed, 143 insertions(+) create mode 100755 pthreads/manual/sched_setaffinity.html (limited to 'pthreads/manual/sched_setaffinity.html') diff --git a/pthreads/manual/sched_setaffinity.html b/pthreads/manual/sched_setaffinity.html new file mode 100755 index 000000000..ec7ef7e0e --- /dev/null +++ b/pthreads/manual/sched_setaffinity.html @@ -0,0 +1,143 @@ + + + + + PTHREAD_CREATE(3) manual page + + + + + + +

POSIX +Threads for Windows – REFERENCE - Pthreads-w32

Reference Index

Table of Contents

Name

sched_setaffinity - set process CPU affinity

sched_getaffinity - get process CPU affinity

Synopsis

#include <sched.h> +

int sched_setaffinity(pid_t pid, +int cpusetsize, +const cpu_set_t *mask);

int sched_getaffinity(pid_t pid, +int cpusetsize, +cpu_set_t *mask);

Description

sched_setaffinity sets the CPU affinity mask of the process +whose ID is pid to the value specified by mask. If pid +is zero, then the calling process is used. The argument cpusetsize +is the length (in bytes) of the data pointed to by mask. +Normally this argument would be specified as sizeof(cpu_set_t).

If the process specified by pid is not currently running on +one of the CPUs specified in mask, then that process is +migrated to one of the CPUs specified in mask.

After a call to sched_setaffinity, the set of CPUs on which +the process will actually run is the intersection of the set +specified in the mask argument and the set of CPUs actually +present on the system.

sched_getaffinity writes the affinity mask of the process +whose ID is pid into the cpu_set_t structure pointed to by +mask. The cpusetsize argument specifies the size (in +bytes) of mask. If pid is zero, then the mask of the +calling process is returned.

Pthreads-w32 currently ignores the cpusetsize +parameter for either function because cpu_set_t is a direct typeset +to the Windows affinity vector type DWORD_PTR.

Windows may require that the requesting process have permission to +set its own CPU affinity or that of another process.

Return Value

On success, sched_setaffinity and sched_getaffinity +return 0. On error, -1 is returned, and errno is set +appropriately.

Errors

EFAULT
+ EINVAL
+ EAGAIN
+ EPERM
+ ESRCH +

+Application Usage

A process's CPU affinity mask determines the set of CPUs on which +it is eligible to run. On a multiprocessor system, setting the CPU +affinity mask can be used to obtain performance benefits. For +example, by dedicating one CPU to a particular process (i.e., setting +the affinity mask of that process to specify a single CPU, and +setting the affinity mask of all other processes to exclude that +CPU), it is possible to ensure maximum execution speed for that +process. Restricting a process to run on a single CPU also avoids the +performance cost caused by the cache invalidation that occurs when a +process ceases to execute on one CPU and then recommences execution +on a different CPU.

A CPU affinity mask is represented by the cpu_set_t structure, a +"CPU set", pointed to by mask. A set of macros for +manipulating CPU sets is described in cpu_set(3).

Copyright

Most of this is taken from the Linux manual page.

Modified by Ross Johnson for use with Pthreads-w32.

Table of Contents

Name +
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Synopsis +
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Description +
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Return + Value +
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Errors +
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Application + Usage
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See + Also
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Copyright
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