23 lines
3.4 KiB
HTML
23 lines
3.4 KiB
HTML
<?xml version="1.0" encoding="ISO-8859-1" standalone="no"?>
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<html xmlns="http://www.w3.org/1999/xhtml"><head><title>hot spot</title><link rel="stylesheet" href="../../jargon.css" type="text/css"/><meta name="generator" content="DocBook XSL Stylesheets V1.61.0"/><link rel="home" href="../index.html" title="The Jargon File"/><link rel="up" href="../H.html" title="H"/><link rel="previous" href="hot-chat.html" title="hot chat"/><link rel="next" href="hotlink.html" title="hotlink"/></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">hot spot</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="hot-chat.html">Prev</a> </td><th width="60%" align="center">H</th><td width="20%" align="right"> <a accesskey="n" href="hotlink.html">Next</a></td></tr></table><hr/></div><dt><a id="hot-spot"/><dt xmlns="" id="hot-spot"><b>hot spot</b>: <span xmlns="http://www.w3.org/1999/xhtml" class="grammar">n.</span></dt></dt><dd><p> 1. [primarily used by C/Unix programmers, but spreading] It is
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received wisdom that in most programs, less than 10% of the code eats 90%
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of the execution time; if one were to graph instruction visits versus code
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addresses, one would typically see a few huge spikes amidst a lot of
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low-level noise. Such spikes are called <span class="firstterm">hot
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spots</span> and are good candidates for heavy optimization or
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<a href="hand-hacking.html"><i class="glossterm">hand-hacking</i></a>. The term is especially used of tight
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loops and recursions in the code's central algorithm, as opposed to (say)
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initial set-up costs or large but infrequent I/O operations. See
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<a href="../T/tune.html"><i class="glossterm">tune</i></a>, <a href="hand-hacking.html"><i class="glossterm">hand-hacking</i></a>. </p></dd><dd><p> 2. The active location of a cursor on a bit-map display. “<span class="quote">Put
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the mouse's hot spot on the ‘ON’ widget and click the left
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button.</span>” </p></dd><dd><p> 3. A screen region that is sensitive to mouse gestures, which
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trigger some action. World Wide Web pages now provide the
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<a href="../C/canonical.html"><i class="glossterm">canonical</i></a> examples; WWW browsers present hypertext
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links as hot spots which, when clicked on, point the browser at another
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document (these are specifically called
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<a href="hotlink.html"><i class="glossterm">hotlink</i></a>s).</p></dd><dd><p> 4. In a massively parallel computer with shared memory, the one
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location that all 10,000 processors are trying to read or write at once
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(perhaps because they are all doing a <a href="../B/busy-wait.html"><i class="glossterm">busy-wait</i></a> on
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the same lock). </p></dd><dd><p> 5. More generally, any place in a hardware design that turns into a
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performance bottleneck due to resource contention.</p></dd><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="hot-chat.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="../H.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="hotlink.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">hot chat </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> hotlink</td></tr></table></div></body></html>
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