aarch64-linux-gnu-4.9/share/doc/libgomp.html/OMP_005fPLACES.html - toolchains/linux-x86/gcc - Git at Google

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 <html>
 <!-- Copyright (C) 2006-2014 Free Software Foundation, Inc.

 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
 any later version published by the Free Software Foundation; with the
 Invariant Sections being "Funding Free Software", the Front-Cover
 texts being (a) (see below), and with the Back-Cover Texts being (b)
 (see below).  A copy of the license is included in the section entitled
 "GNU Free Documentation License".

 (a) The FSF's Front-Cover Text is:

 A GNU Manual

 (b) The FSF's Back-Cover Text is:

 You have freedom to copy and modify this GNU Manual, like GNU
      software.  Copies published by the Free Software Foundation raise
      funds for GNU development. -->
 <!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
 <head>
 <title>GNU libgomp: OMP_PLACES</title>

 <meta name="description" content="GNU libgomp: OMP_PLACES">
 <meta name="keywords" content="GNU libgomp: OMP_PLACES">
 <meta name="resource-type" content="document">
 <meta name="distribution" content="global">
 <meta name="Generator" content="makeinfo">
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 <link href="index.html#Top" rel="start" title="Top">
 <link href="Library-Index.html#Library-Index" rel="index" title="Library Index">
 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
 <link href="Environment-Variables.html#Environment-Variables" rel="up" title="Environment Variables">
 <link href="OMP_005fSTACKSIZE.html#OMP_005fSTACKSIZE" rel="next" title="OMP_STACKSIZE">
 <link href="OMP_005fPROC_005fBIND.html#OMP_005fPROC_005fBIND" rel="prev" title="OMP_PROC_BIND">
 <style type="text/css">
 <!--
 a.summary-letter {text-decoration: none}
 blockquote.smallquotation {font-size: smaller}
 div.display {margin-left: 3.2em}
 div.example {margin-left: 3.2em}
 div.indentedblock {margin-left: 3.2em}
 div.lisp {margin-left: 3.2em}
 div.smalldisplay {margin-left: 3.2em}
 div.smallexample {margin-left: 3.2em}
 div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
 div.smalllisp {margin-left: 3.2em}
 kbd {font-style:oblique}
 pre.display {font-family: inherit}
 pre.format {font-family: inherit}
 pre.menu-comment {font-family: serif}
 pre.menu-preformatted {font-family: serif}
 pre.smalldisplay {font-family: inherit; font-size: smaller}
 pre.smallexample {font-size: smaller}
 pre.smallformat {font-family: inherit; font-size: smaller}
 pre.smalllisp {font-size: smaller}
 span.nocodebreak {white-space:nowrap}
 span.nolinebreak {white-space:nowrap}
 span.roman {font-family:serif; font-weight:normal}
 span.sansserif {font-family:sans-serif; font-weight:normal}
 ul.no-bullet {list-style: none}
 -->
 </style>


 </head>

 <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
 <a name="OMP_005fPLACES"></a>
 <div class="header">
 <p>
 Next: <a href="OMP_005fSTACKSIZE.html#OMP_005fSTACKSIZE" accesskey="n" rel="next">OMP_STACKSIZE</a>, Previous: <a href="OMP_005fPROC_005fBIND.html#OMP_005fPROC_005fBIND" accesskey="p" rel="prev">OMP_PROC_BIND</a>, Up: <a href="Environment-Variables.html#Environment-Variables" accesskey="u" rel="up">Environment Variables</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Library-Index.html#Library-Index" title="Index" rel="index">Index</a>]</p>
 </div>
 <hr>
 <a name="OMP_005fPLACES-_002d_002d-Specifies-on-which-CPUs-the-theads-should-be-placed"></a>
 <h3 class="section">3.9 <code>OMP_PLACES</code> &ndash; Specifies on which CPUs the theads should be placed</h3>
 <a name="index-Environment-Variable-8"></a>
 <dl compact="compact">
 <dt><em>Description</em>:</dt>
 <dd><p>The thread placement can be either specified using an abstract name or by an
 explicit list of the places.  The abstract names <code>threads</code>, <code>cores</code>
 and <code>sockets</code> can be optionally followed by a positive number in
 parentheses, which denotes the how many places shall be created.  With
 <code>threads</code> each place corresponds to a single hardware thread; <code>cores</code>
 to a single core with the corresponding number of hardware threads; and with
 <code>sockets</code> the place corresponds to a single socket.  The resulting
 placement can be shown by setting the <code>OMP_DISPLAY_ENV</code> environment
 variable.
 </p>
 <p>Alternatively, the placement can be specified explicitly as comma-separated
 list of places.  A place is specified by set of nonnegative numbers in curly
 braces, denoting the denoting the hardware threads.  The hardware threads
 belonging to a place can either be specified as comma-separated list of
 nonnegative thread numbers or using an interval.  Multiple places can also be
 either specified by a comma-separated list of places or by an interval.  To
 specify an interval, a colon followed by the count is placed after after
 the hardware thread number or the place.  Optionally, the length can be
 followed by a colon and the stride number &ndash; otherwise a unit stride is
 assumed.  For instance, the following specifies the same places list:
 <code>&quot;{0,1,2}, {3,4,6}, {7,8,9}, {10,11,12}&quot;</code>;
 <code>&quot;{0:3}, {3:3}, {7:3}, {10:3}&quot;</code>; and <code>&quot;{0:2}:4:3&quot;</code>.
 </p>
 <p>If <code>OMP_PLACES</code> and <code>GOMP_CPU_AFFINITY</code> are unset and
 <code>OMP_PROC_BIND</code> is either unset or <code>false</code>, threads may be moved
 between CPUs following no placement policy.
 </p>
 </dd>
 <dt><em>See also</em>:</dt>
 <dd><p><a href="OMP_005fPROC_005fBIND.html#OMP_005fPROC_005fBIND">OMP_PROC_BIND</a>, <a href="GOMP_005fCPU_005fAFFINITY.html#GOMP_005fCPU_005fAFFINITY">GOMP_CPU_AFFINITY</a>, <a href="omp_005fget_005fproc_005fbind.html#omp_005fget_005fproc_005fbind">omp_get_proc_bind</a>,
 <a href="OMP_005fDISPLAY_005fENV.html#OMP_005fDISPLAY_005fENV">OMP_DISPLAY_ENV</a>
 </p>
 </dd>
 <dt><em>Reference</em>:</dt>
 <dd><p><a href="http://www.openmp.org/">OpenMP specification v4.0</a>, Section 4.5
 </p></dd>
 </dl>


 <hr>
 <div class="header">
 <p>
 Next: <a href="OMP_005fSTACKSIZE.html#OMP_005fSTACKSIZE" accesskey="n" rel="next">OMP_STACKSIZE</a>, Previous: <a href="OMP_005fPROC_005fBIND.html#OMP_005fPROC_005fBIND" accesskey="p" rel="prev">OMP_PROC_BIND</a>, Up: <a href="Environment-Variables.html#Environment-Variables" accesskey="u" rel="up">Environment Variables</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Library-Index.html#Library-Index" title="Index" rel="index">Index</a>]</p>
 </div>


 </body>
 </html>
	<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
	<html>
	<!-- Copyright (C) 2006-2014 Free Software Foundation, Inc.

	Permission is granted to copy, distribute and/or modify this document
	under the terms of the GNU Free Documentation License, Version 1.3 or
	any later version published by the Free Software Foundation; with the
	Invariant Sections being "Funding Free Software", the Front-Cover
	texts being (a) (see below), and with the Back-Cover Texts being (b)
	(see below). A copy of the license is included in the section entitled
	"GNU Free Documentation License".

	(a) The FSF's Front-Cover Text is:

	A GNU Manual

	(b) The FSF's Back-Cover Text is:

	You have freedom to copy and modify this GNU Manual, like GNU
	software. Copies published by the Free Software Foundation raise
	funds for GNU development. -->
	<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
	<head>
	<title>GNU libgomp: OMP_PLACES</title>

	<meta name="description" content="GNU libgomp: OMP_PLACES">
	<meta name="keywords" content="GNU libgomp: OMP_PLACES">
	<meta name="resource-type" content="document">
	<meta name="distribution" content="global">
	<meta name="Generator" content="makeinfo">
	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
	<link href="index.html#Top" rel="start" title="Top">
	<link href="Library-Index.html#Library-Index" rel="index" title="Library Index">
	<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
	<link href="Environment-Variables.html#Environment-Variables" rel="up" title="Environment Variables">
	<link href="OMP_005fSTACKSIZE.html#OMP_005fSTACKSIZE" rel="next" title="OMP_STACKSIZE">
	<link href="OMP_005fPROC_005fBIND.html#OMP_005fPROC_005fBIND" rel="prev" title="OMP_PROC_BIND">
	<style type="text/css">
	<!--
	a.summary-letter {text-decoration: none}
	blockquote.smallquotation {font-size: smaller}
	div.display {margin-left: 3.2em}
	div.example {margin-left: 3.2em}
	div.indentedblock {margin-left: 3.2em}
	div.lisp {margin-left: 3.2em}
	div.smalldisplay {margin-left: 3.2em}
	div.smallexample {margin-left: 3.2em}
	div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
	div.smalllisp {margin-left: 3.2em}
	kbd {font-style:oblique}
	pre.display {font-family: inherit}
	pre.format {font-family: inherit}
	pre.menu-comment {font-family: serif}
	pre.menu-preformatted {font-family: serif}
	pre.smalldisplay {font-family: inherit; font-size: smaller}
	pre.smallexample {font-size: smaller}
	pre.smallformat {font-family: inherit; font-size: smaller}
	pre.smalllisp {font-size: smaller}
	span.nocodebreak {white-space:nowrap}
	span.nolinebreak {white-space:nowrap}
	span.roman {font-family:serif; font-weight:normal}
	span.sansserif {font-family:sans-serif; font-weight:normal}
	ul.no-bullet {list-style: none}
	-->
	</style>


	</head>

	<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
	<a name="OMP_005fPLACES"></a>
	<div class="header">
	<p>
	Next: <a href="OMP_005fSTACKSIZE.html#OMP_005fSTACKSIZE" accesskey="n" rel="next">OMP_STACKSIZE</a>, Previous: <a href="OMP_005fPROC_005fBIND.html#OMP_005fPROC_005fBIND" accesskey="p" rel="prev">OMP_PROC_BIND</a>, Up: <a href="Environment-Variables.html#Environment-Variables" accesskey="u" rel="up">Environment Variables</a>   [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Library-Index.html#Library-Index" title="Index" rel="index">Index</a>]</p>
	</div>
	<hr>
	<a name="OMP_005fPLACES-_002d_002d-Specifies-on-which-CPUs-the-theads-should-be-placed"></a>
	<h3 class="section">3.9 <code>OMP_PLACES</code> – Specifies on which CPUs the theads should be placed</h3>
	<a name="index-Environment-Variable-8"></a>
	<dl compact="compact">
	<dt><em>Description</em>:</dt>
	<dd><p>The thread placement can be either specified using an abstract name or by an
	explicit list of the places. The abstract names <code>threads</code>, <code>cores</code>
	and <code>sockets</code> can be optionally followed by a positive number in
	parentheses, which denotes the how many places shall be created. With
	<code>threads</code> each place corresponds to a single hardware thread; <code>cores</code>
	to a single core with the corresponding number of hardware threads; and with
	<code>sockets</code> the place corresponds to a single socket. The resulting
	placement can be shown by setting the <code>OMP_DISPLAY_ENV</code> environment
	variable.
	</p>
	<p>Alternatively, the placement can be specified explicitly as comma-separated
	list of places. A place is specified by set of nonnegative numbers in curly
	braces, denoting the denoting the hardware threads. The hardware threads
	belonging to a place can either be specified as comma-separated list of
	nonnegative thread numbers or using an interval. Multiple places can also be
	either specified by a comma-separated list of places or by an interval. To
	specify an interval, a colon followed by the count is placed after after
	the hardware thread number or the place. Optionally, the length can be
	followed by a colon and the stride number – otherwise a unit stride is
	assumed. For instance, the following specifies the same places list:
	<code>"{0,1,2}, {3,4,6}, {7,8,9}, {10,11,12}"</code>;
	<code>"{0:3}, {3:3}, {7:3}, {10:3}"</code>; and <code>"{0:2}:4:3"</code>.
	</p>
	<p>If <code>OMP_PLACES</code> and <code>GOMP_CPU_AFFINITY</code> are unset and
	<code>OMP_PROC_BIND</code> is either unset or <code>false</code>, threads may be moved
	between CPUs following no placement policy.
	</p>
	</dd>
	<dt><em>See also</em>:</dt>
	<dd><p><a href="OMP_005fPROC_005fBIND.html#OMP_005fPROC_005fBIND">OMP_PROC_BIND</a>, <a href="GOMP_005fCPU_005fAFFINITY.html#GOMP_005fCPU_005fAFFINITY">GOMP_CPU_AFFINITY</a>, <a href="omp_005fget_005fproc_005fbind.html#omp_005fget_005fproc_005fbind">omp_get_proc_bind</a>,
	<a href="OMP_005fDISPLAY_005fENV.html#OMP_005fDISPLAY_005fENV">OMP_DISPLAY_ENV</a>
	</p>
	</dd>
	<dt><em>Reference</em>:</dt>
	<dd><p><a href="http://www.openmp.org/">OpenMP specification v4.0</a>, Section 4.5
	</p></dd>
	</dl>



	<hr>
	<div class="header">
	<p>
	Next: <a href="OMP_005fSTACKSIZE.html#OMP_005fSTACKSIZE" accesskey="n" rel="next">OMP_STACKSIZE</a>, Previous: <a href="OMP_005fPROC_005fBIND.html#OMP_005fPROC_005fBIND" accesskey="p" rel="prev">OMP_PROC_BIND</a>, Up: <a href="Environment-Variables.html#Environment-Variables" accesskey="u" rel="up">Environment Variables</a>   [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Library-Index.html#Library-Index" title="Index" rel="index">Index</a>]</p>
	</div>



	</body>
	</html>