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101 lines
5.2 KiB
HTML
101 lines
5.2 KiB
HTML
4 years ago
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<html lang="en">
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<head>
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<title>Executing - GNU gprof</title>
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<meta http-equiv="Content-Type" content="text/html">
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<meta name="description" content="GNU gprof">
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<meta name="generator" content="makeinfo 4.13">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="prev" href="Compiling.html#Compiling" title="Compiling">
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<link rel="next" href="Invoking.html#Invoking" title="Invoking">
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<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
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<!--
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This file documents the gprof profiler of the GNU system.
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Copyright (C) 1988-2015 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3
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or any later version published by the Free Software Foundation;
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with no Invariant Sections, with no Front-Cover Texts, and with no
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Back-Cover Texts. A copy of the license is included in the
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section entitled ``GNU Free Documentation License''.
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-->
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<meta http-equiv="Content-Style-Type" content="text/css">
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<style type="text/css"><!--
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pre.display { font-family:inherit }
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span.sansserif { font-family:sans-serif; font-weight:normal; }
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--></style>
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</head>
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<body>
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<div class="node">
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<a name="Executing"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="Invoking.html#Invoking">Invoking</a>,
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Previous: <a rel="previous" accesskey="p" href="Compiling.html#Compiling">Compiling</a>,
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Up: <a rel="up" accesskey="u" href="index.html#Top">Top</a>
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<hr>
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</div>
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<h2 class="chapter">3 Executing the Program</h2>
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<p>Once the program is compiled for profiling, you must run it in order to
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generate the information that <code>gprof</code> needs. Simply run the program
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as usual, using the normal arguments, file names, etc. The program should
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run normally, producing the same output as usual. It will, however, run
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somewhat slower than normal because of the time spent collecting and
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writing the profile data.
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<p>The way you run the program—the arguments and input that you give
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it—may have a dramatic effect on what the profile information shows. The
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profile data will describe the parts of the program that were activated for
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the particular input you use. For example, if the first command you give
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to your program is to quit, the profile data will show the time used in
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initialization and in cleanup, but not much else.
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<p>Your program will write the profile data into a file called <samp><span class="file">gmon.out</span></samp>
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just before exiting. If there is already a file called <samp><span class="file">gmon.out</span></samp>,
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its contents are overwritten. There is currently no way to tell the
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program to write the profile data under a different name, but you can rename
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the file afterwards if you are concerned that it may be overwritten.
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<p>In order to write the <samp><span class="file">gmon.out</span></samp> file properly, your program must exit
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normally: by returning from <code>main</code> or by calling <code>exit</code>. Calling
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the low-level function <code>_exit</code> does not write the profile data, and
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neither does abnormal termination due to an unhandled signal.
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<p>The <samp><span class="file">gmon.out</span></samp> file is written in the program's <em>current working
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directory</em> at the time it exits. This means that if your program calls
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<code>chdir</code>, the <samp><span class="file">gmon.out</span></samp> file will be left in the last directory
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your program <code>chdir</code>'d to. If you don't have permission to write in
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this directory, the file is not written, and you will get an error message.
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<p>Older versions of the <span class="sc">gnu</span> profiling library may also write a file
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called <samp><span class="file">bb.out</span></samp>. This file, if present, contains an human-readable
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listing of the basic-block execution counts. Unfortunately, the
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appearance of a human-readable <samp><span class="file">bb.out</span></samp> means the basic-block
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counts didn't get written into <samp><span class="file">gmon.out</span></samp>.
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The Perl script <code>bbconv.pl</code>, included with the <code>gprof</code>
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source distribution, will convert a <samp><span class="file">bb.out</span></samp> file into
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a format readable by <code>gprof</code>. Invoke it like this:
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<pre class="smallexample"> bbconv.pl < bb.out > <var>bh-data</var>
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</pre>
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<p>This translates the information in <samp><span class="file">bb.out</span></samp> into a form that
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<code>gprof</code> can understand. But you still need to tell <code>gprof</code>
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about the existence of this translated information. To do that, include
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<var>bb-data</var> on the <code>gprof</code> command line, <em>along with
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</em><samp><span class="file">gmon.out</span></samp>, like this:
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<pre class="smallexample"> gprof <var>options</var> <var>executable-file</var> gmon.out <var>bb-data</var> [<var>yet-more-profile-data-files</var>...] [> <var>outfile</var>]
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</pre>
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</body></html>
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