1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Unused X86 optimization</title> 5<link rel="stylesheet" href="../../../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../../../index.html" title="Boost.Sort"> 8<link rel="up" href="../rationale.html" title="Rationale"> 9<link rel="prev" href="unstable_sort.html" title="Unstable Sorting"> 10<link rel="next" href="lookup.html" title="Lookup Table?"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="unstable_sort.html"><img src="../../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../rationale.html"><img src="../../../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../../index.html"><img src="../../../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="lookup.html"><img src="../../../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h6 class="title"> 27<a name="sort.single_thread.spreadsort.sort_hpp.rationale.optimization"></a><a class="link" href="optimization.html" title="Unused X86 optimization">Unused 28 X86 optimization</a> 29</h6></div></div></div> 30<p> 31 Though the ideal <span class="emphasis"><em>max_splits</em></span> for <code class="computeroutput">n < 1 32 million</code> (or so) on x86 <span class="emphasis"><em>seems</em></span> to be substantially 33 larger, enabling a roughly 15% speedup for such tests, this optimization 34 isn't general, and doesn't apply for <code class="computeroutput">n > 1 million</code>. 35 A too large <span class="emphasis"><em>max_splits</em></span> can cause sort to take 36 more than twice as long, so it should be set on the low end of the 37 reasonable range, where it is right now. 38 </p> 39</div> 40<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 41<td align="left"></td> 42<td align="right"><div class="copyright-footer">Copyright © 2014-2017 Steven 43 Ross, Francisco Tapia, Orson Peters<p> 44 Distributed under the <a href="http://boost.org/LICENSE_1_0.txt" target="_top">Boost 45 Software License, Version 1.0</a>. 46 </p> 47</div></td> 48</tr></table> 49<hr> 50<div class="spirit-nav"> 51<a accesskey="p" href="unstable_sort.html"><img src="../../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../rationale.html"><img src="../../../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../../index.html"><img src="../../../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="lookup.html"><img src="../../../../../../../../../doc/src/images/next.png" alt="Next"></a> 52</div> 53</body> 54</html> 55
