1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" 2 "http://www.w3.org/TR/html4/strict.dtd"> 3<html> 4<head> 5 <META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" /> 6 <title>Clang - Performance</title> 7 <link type="text/css" rel="stylesheet" href="menu.css" /> 8 <link type="text/css" rel="stylesheet" href="content.css" /> 9 <style type="text/css"> 10</style> 11</head> 12<body> 13 14<!--#include virtual="menu.html.incl"--> 15 16<div id="content"> 17 18<!--*************************************************************************--> 19<h1>Clang - Performance</h1> 20<!--*************************************************************************--> 21 22<p>This page shows the compile time performance of Clang on two 23interesting benchmarks: 24<ul> 25 <li><i>Sketch</i>: The Objective-C example application shipped on 26 Mac OS X as part of Xcode. <i>Sketch</i> is indicative of a 27 "typical" Objective-C app. The source itself has a relatively 28 small amount of code (~7,500 lines of source code), but it relies 29 on the extensive Cocoa APIs to build its functionality. Like many 30 Objective-C applications, it includes <tt>Cocoa/Cocoa.h</tt> in 31 all of its source files, which represents a significant stress 32 test of the front-end's performance on lexing, preprocessing, 33 parsing, and syntax analysis.</li> 34 <li><i>176.gcc</i>: This is the gcc-2.7.2.2 code base as present in 35 SPECINT 2000. In contrast to Sketch, <i>176.gcc</i> consists of a 36 large amount of C source code (~200,000 lines) with few system 37 dependencies. This stresses the back-end's performance on generating 38 assembly code and debug information.</li> 39</ul> 40</p> 41 42<p> 43For previous performance numbers, please 44go <a href="performance-2009-03-02.html">here</a>. 45</p> 46 47<!--*************************************************************************--> 48<h2><a name="experiments">Experiments</a></h2> 49<!--*************************************************************************--> 50 51<p>Measurements are done by running a full build (using xcodebuild or 52make for Sketch and 176.gcc respectively) using Clang and gcc 4.2 as 53compilers.</p> 54 55<p>In order to track the performance of various subsystems the timings 56have been broken down into separate stages where possible. This is 57done by over-riding the CC environment variable used during the build 58to point to one of a few simple shell scripts which may skip part of 59the build. 60 61<ul> 62 <li><tt>non-compiler</tt>: The overhead of the build system itself; 63 for Sketch this also includes the time to build/copy various 64 non-source code resource files.</li> 65 <li><tt>+ driver</tt>: Add execution of the driver, but do not execute any 66 commands (by using the -### driver option).</li> 67 <li><tt>+ pch gen</tt>: Add generation of PCH files (if used).</li> 68 <li><tt>+ syntax</tt>: Add preprocessing, parsing, and semantic checking of 69 source files.</li> 70 <li><tt>+ IRgen</tt>: Add generation of LLVM IR (gcc has no 71 corresponding phase).</li> 72 <li><tt>+ codegen</tt>: Add generation of assembler files.</li> 73 <li><tt>+ assembler</tt>: Add assembler time to generate .o files.</li> 74 <li><tt>+ linker</tt>: Add linker time.</li> 75</ul> 76</p> 77 78<p>This set of stages is chosen to be approximately additive, that is each 79subsequent stage simply adds some additional processing. The timings measure the 80delta of the given stage from the previous one. For example, the timings 81for <tt>+ syntax</tt> below show the difference of running with <tt>+ 82syntax</tt> versus the times for <tt>+ pch gen</tt>. This amounts to a fairly 83accurate measure of only the time to perform preprocessing, parsing, and 84semantic analysis after PCH generation is done.</p> 85 86<!--*************************************************************************--> 87<h2><a name="timings">Timing Results</a></h2> 88<!--*************************************************************************--> 89 90<!--=======================================================================--> 91<h3><a name="2009-06-26">2009-06-26</a></h3> 92<!--=======================================================================--> 93 94<a href="timing-data/2009-06-26/sketch.pdf"> 95<img class="img_slide" 96 src="timing-data/2009-06-26/sketch.png" alt="Sketch Timings"/> 97</a> 98 99<a href="timing-data/2009-06-26/176.gcc.pdf"> 100<img class="img_slide" 101 src="timing-data/2009-06-26/176.gcc.png" alt="176.gcc Timings"/> 102</a> 103 104</div> 105</body> 106</html> 107
