58 lines
2.4 KiB
HTML
58 lines
2.4 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<meta name="Copyright" content="Copyright (c) 2006 by IBM Corporation">
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<title>Read/write locks do not favor writers</title>
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<h2>Read/write locks do not favor writers</h2>
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<p>The i5/OS implementation of read/write locks does not favor writers. If
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your application has a large number of readers contending for the same lock,
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the writers may not be allowed to write.</p>
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<p>The i5/OS implementation of <strong>pthread_rwlock_tryrdlock</strong>(),
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for example, does not completely honor the Single UNIX Specification in its
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treatment of reader/writer contention.</p>
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<p>The standard states the following: "The function pthread_rwlock_tryrdlock()
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applies a read lock as in the pthread_rwlock_rdlock() function with the
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exception that the function fails if any thread holds a write lock on rwlock or
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there are writers blocked on rwlock."</p>
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<p>In the i5/OS implementation, if <strong>pthread_rwlock_tryrdlock</strong>()
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is used on a read/write lock that has multiple readers holding the lock and
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multiple waiting writers blocked on the lock, the <strong>
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pthread_rwlock_tryrdlock</strong>() are allowed to complete successfully.</p>
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<a href="rzah4mst.htm">Pthread APIs</a> |
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<a href="aplist.htm">APIs by category</a></td>
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