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gerrit-public.fairphone.software / fp2-dev / platform / external / clang / e2b6833d445c7a4ce64f1816c05f176ba1740aca / . / www / performance.html
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19<h1>Clang - Performance</h1>
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Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]22<p>This page shows the compile time performance of Clang on two
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]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
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]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>
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]34 <li><i>176.gcc</i>: This is the gcc-2.7.2.2 code base as present in
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]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>
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]39</ul>
40</p>
41
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]42<p>
43For previous performance numbers, please
44go <a href="performance-2008-10-31.html">here</a>.
45</p>
46
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]47<!--*************************************************************************-->
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]48<h2><a name="experiments">Experiments</a></h2>
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]49<!--*************************************************************************-->
50
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]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; gcc is run both with and without the new clang driver (ccc)
54in order to evaluate the overhead of the driver itself.</p>
55
56<p>In order to track the performance of various subsystems the timings
57have been broken down into separate stages where possible. This is
58done by over-riding the CC environment variable used during the build
59to point to one of a few simple shell scripts which may skip part of
60the build.
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]61
62<ul>
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]63 <li><tt>non-compiler</tt>: The overhead of the build system itself;
64 for Sketch this also includes the time to build/copy various
65 non-source code resource files.</li>
66 <li><tt>+ driver</tt>: Add execution of the driver, but do not execute any
67 commands (by using the -### driver option).</li>
68 <li><tt>+ pch gen</tt>: Add generation of PCH files.</li>
69 <li><tt>+ cpp</tt>: Add preprocessing of source files (this time is
70 include in syntax for gcc).</li>
71 <li><tt>+ parse</tt>: Add parsing of source files (this time is
72 include in syntax for gcc).</li>
73 <li><tt>+ syntax</tt>: Add semantic checking of source files (for
74 gcc, this includes preprocessing and parsing as well).</li>
75 <li><tt>+ IRgen</tt>: Add generation of LLVM IR (gcc has no
76 corresponding phase).</li>
77 <li><tt>+ codegen</tt>: Add generation of assembler files.</li>
78 <li><tt>+ assembler</tt>: Add assembler time to generate .o files.</li>
79 <li><tt>+ linker</tt>: Add linker time.</li>
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]80</ul>
81</p>
82
83<p>This set of stages is chosen to be approximately additive, that is
84each subsequent stage simply adds some additional processing. The
85timings measure the delta of the given stage from the previous
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]86one. For example, the timings for <tt>+ syntax</tt> below show the
87difference of running with <tt>+ syntax</tt> versus running with <tt>+
88parse</tt> (for clang) or <tt>+ driver</tt> with gcc. This amounts to
89a fairly accurate measure of only the time to perform semantic
90analysis (and preprocessing/parsing, in the case of gcc).</p>
Chris Lattner09d84ba2008-11-01 01:46:51 +0000[diff] [blame]91
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]92<!--*************************************************************************-->
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]93<h2><a name="timings">Timing Results</a></h2>
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]94<!--*************************************************************************-->
95
96<!--=======================================================================-->
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]97<h3><a name="2009-03-02">2009-03-02</a></h3>
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]98<!--=======================================================================-->
99
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]100<a href="timing-data/2009-03-02/sketch.pdf">
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]101<img class="img_slide"
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]102 src="timing-data/2009-03-02/sketch.png" alt="Sketch Timings"/>
103</a>
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]104
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]105<a href="timing-data/2009-03-02/176.gcc.pdf">
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]106<img class="img_slide"
Daniel Dunbar3d1c9462009-03-04 00:04:28 +0000[diff] [blame]107 src="timing-data/2009-03-02/176.gcc.png" alt="176.gcc Timings"/>
108</a>
Daniel Dunbar2336d1f2008-11-01 01:14:36 +0000[diff] [blame]109
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