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Majorly improved. Still a lot to do, but the structure is better. git-svn-id: svn://svn.valgrind.org/valgrind/trunk@1324
57 lines
1.8 KiB
HTML
57 lines
1.8 KiB
HTML
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<html>
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<title>Helgrind: a data-race detector</title>
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</head>
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<a name="hg-top"></a>
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<h2>6 Helgrind: a data-race detector</h2>
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To use this skin, you must specify <code>--skin=helgrind</code> on the
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Valgrind command line.
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<p>
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Helgrind is a Valgrind skin for detecting data races in C and C++ programs
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that use the Pthreads library.
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<p>
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It uses the Eraser algorithm described in
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<blockquote>
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Eraser: A Dynamic Data Race Detector for Multithreaded Programs<br>
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Stefan Savage, Michael Burrows, Greg Nelson, Patrick Sobalvarro and
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Thomas Anderson<br>
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ACM Transactions on Computer Systems, 15(4):391-411<br>
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November 1997.
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</blockquote>
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We also incorporate significant improvements from this paper:
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<blockquote>
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Runtime Checking of Multithreaded Applications with Visual Threads
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Jerry J. Harrow, Jr.<br>
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Proceedings of the 7th International SPIN Workshop on Model Checking of
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Software<br>
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Stanford, California, USA<br>
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August 2000<br>
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LNCS 1885, pp331--342<br>
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K. Havelund, J. Penix, and W. Visser, editors.<br>
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</blockquote>
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<p>
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Basically what Helgrind does is to look for memory locations which are
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accessed by more than one thread. For each such location, Helgrind
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records which of the program's (pthread_mutex_)locks were held by the
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accessing thread at the time of the access. The hope is to discover
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that there is indeed at least one lock which is used by all threads to
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protect that location. If no such lock can be found, then there is
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(apparently) no consistent locking strategy being applied for that
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location, and so a possible data race might result.
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<p>
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There's a lot of other sophistication in the Helgrind skin, aimed at
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reducing the number of false reports, and at producing useful error
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reports. We hope to have more documentation soon.
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</body>
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</html>
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