<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
<html>
|
<!-- Copyright (C) 2006-2016 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: CUDA Streams Usage</title>
|
|
<meta name="description" content="GNU libgomp: CUDA Streams Usage">
|
<meta name="keywords" content="GNU libgomp: CUDA Streams Usage">
|
<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="index.html#Top" rel="up" title="Top">
|
<link href="OpenACC-Library-Interoperability.html#OpenACC-Library-Interoperability" rel="next" title="OpenACC Library Interoperability">
|
<link href="GCC_005fACC_005fNOTIFY.html#GCC_005fACC_005fNOTIFY" rel="prev" title="GCC_ACC_NOTIFY">
|
<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="CUDA-Streams-Usage"></a>
|
<div class="header">
|
<p>
|
Next: <a href="OpenACC-Library-Interoperability.html#OpenACC-Library-Interoperability" accesskey="n" rel="next">OpenACC Library Interoperability</a>, Previous: <a href="OpenACC-Environment-Variables.html#OpenACC-Environment-Variables" accesskey="p" rel="prev">OpenACC Environment Variables</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</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="CUDA-Streams-Usage-1"></a>
|
<h2 class="chapter">7 CUDA Streams Usage</h2>
|
|
<p>This applies to the <code>nvptx</code> plugin only.
|
</p>
|
<p>The library provides elements that perform asynchronous movement of
|
data and asynchronous operation of computing constructs. This
|
asynchronous functionality is implemented by making use of CUDA
|
streams<a name="DOCF1" href="#FOOT1"><sup>1</sup></a>.
|
</p>
|
<p>The primary means by that the asychronous functionality is accessed
|
is through the use of those OpenACC directives which make use of the
|
<code>async</code> and <code>wait</code> clauses. When the <code>async</code> clause is
|
first used with a directive, it creates a CUDA stream. If an
|
<code>async-argument</code> is used with the <code>async</code> clause, then the
|
stream is associated with the specified <code>async-argument</code>.
|
</p>
|
<p>Following the creation of an association between a CUDA stream and the
|
<code>async-argument</code> of an <code>async</code> clause, both the <code>wait</code>
|
clause and the <code>wait</code> directive can be used. When either the
|
clause or directive is used after stream creation, it creates a
|
rendezvous point whereby execution waits until all operations
|
associated with the <code>async-argument</code>, that is, stream, have
|
completed.
|
</p>
|
<p>Normally, the management of the streams that are created as a result of
|
using the <code>async</code> clause, is done without any intervention by the
|
caller. This implies the association between the <code>async-argument</code>
|
and the CUDA stream will be maintained for the lifetime of the program.
|
However, this association can be changed through the use of the library
|
function <code>acc_set_cuda_stream</code>. When the function
|
<code>acc_set_cuda_stream</code> is called, the CUDA stream that was
|
originally associated with the <code>async</code> clause will be destroyed.
|
Caution should be taken when changing the association as subsequent
|
references to the <code>async-argument</code> refer to a different
|
CUDA stream.
|
</p>
|
|
|
|
<div class="footnote">
|
<hr>
|
<h4 class="footnotes-heading">Footnotes</h4>
|
|
<h3><a name="FOOT1" href="#DOCF1">(1)</a></h3>
|
<p>See "Stream Management" in "CUDA Driver API",
|
TRM-06703-001, Version 5.5, for additional information</p>
|
</div>
|
<hr>
|
<div class="header">
|
<p>
|
Next: <a href="OpenACC-Library-Interoperability.html#OpenACC-Library-Interoperability" accesskey="n" rel="next">OpenACC Library Interoperability</a>, Previous: <a href="OpenACC-Environment-Variables.html#OpenACC-Environment-Variables" accesskey="p" rel="prev">OpenACC Environment Variables</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</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>
|
