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Adding swig, gitignore, hgignore
author Nomad
date Mon, 21 Oct 2013 10:42:27 +0200
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1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
2 <HTML>
3 <HEAD>
4 <TITLE>ccache</TITLE>
5 </HEAD>
6 <BODY BGCOLOR="#ffffff" TEXT="#000000" VLINK="#292555" LINK="#292555" ALINK="#cc0033">
7 <h2>ccache</h2>
8
9 ccache is a compiler cache. It acts as a caching pre-processor to
10 C/C++ compilers, using the -E compiler switch and a hash to detect
11 when a compilation can be satisfied from cache. This often results in
12 a 5 to 10 times speedup in common compilations.<p>
13
14 The idea came from Erik Thiele wrote the original <a
15 href="http://compilercache.sourceforge.net/">compilercache</a> program
16 as a bourne shell script. ccache is a re-implementation of Erik's idea
17 in C with more features and better performance.<p>
18
19 <h2>Latest release</h2>
20
21 The latest release is ccache 2.4.
22
23 <ul>
24 <li>Added CCACHE_READONLY option
25 <li>Added CCACHE_TEMPDIR option
26 <li>fixed handling of hard-linked compilers on AIX
27 <li>added O_BINARY support, to try and support win32 compiles
28 <li>show cache directory in stats output
29 <li>fixed handling of HOME environment variable
30 </ul>
31
32 See the <a href="ccache-man.html">manual page</a> for details
33 on the new options.<p>
34
35 You can get this release from the <a href="http://ccache.samba.org/ftp/ccache/">download directory</a>
36
37 <p>NOTE! This release changes the hash input slighly, so you will
38 probably find that you will not get any hits against your existing
39 cache when you upgrade.
40
41 <h2>Why bother?</h2>
42
43 Why bother with a compiler cache? If you ever run "make clean; make"
44 then you can probably benefit from ccache. It is very common for
45 developers to do a clean build of a project for a whole host of
46 reasons, and this throws away all the information from your previous
47 compiles.<p>
48
49 By using ccache you can get exactly the same effect as "make clean;
50 make" but much faster. It also helps a lot when doing RPM builds,
51 as RPM can make doing incremental builds tricky.<p>
52
53 I put the effort into writing ccache for 2 reasons. The first is the
54 Samba build farm
55 (<a href="http://build.samba.org/">http://build.samba.org/</a>)
56 which constantly does clean builds of Samba on about 30 machines after each
57 CVS commit. On some of those machines the build took over an hour. By
58 using ccache we get the same effect as clean builds but about 6 times
59 faster.<p>
60
61 The second reason is the autobuild system I used to run for
62 Quantum. That system builds our whole Linux based OS from scratch
63 after every CVS commit to catch compilation problems quickly. Using
64 ccache those builds are much faster.
65
66 <h2>Is it safe?</h2>
67
68 Yes. The most important aspect of a compiler cache is to <b>always</b>
69 produce exactly the same output that the real compiler would
70 produce. The includes providing exactly the same object files and
71 exactly the same compiler warnings that would be produced if you use
72 the real compiler. The only way you should be able to tell that you
73 are using ccache is the speed.<p>
74
75 I have coded ccache very carefully to try to provide these guarantees.
76
77 <h2>Features</h2>
78
79 <ul>
80 <li> keeps statistics on hits/misses
81 <li> automatic cache size management
82 <li> can cache compiles that generate warnings
83 <li> easy installation
84 <li> very low overhead
85 <li> uses hard links where possible to avoid copies
86 </ul>
87
88 <h2>Documentation</h2>
89
90 See the <a href="ccache-man.html">manual page</a>
91
92
93 <h2>Performance</h2>
94
95 Here are some results for compiling Samba on my Linux laptop. I have
96 also included the results of using Erik's compilercache program
97 (version 1.0.10) for comparison.<p>
98
99 <table border=1>
100 <tr><th> </th> <th>&nbsp;&nbsp;&nbsp;&nbsp;ccache</th> <th>&nbsp;compilercache</th> </tr>
101 <tr><td>normal </td> <td align=right>13m 4s </td><td align=right>13m 4s</td> </tr>
102 <tr><td>uncached </td> <td align=right>13m 15s </td><td align=right>15m 41s</td> </tr>
103 <tr><td>cached </td> <td align=right>2m 45s </td><td align=right>4m 26s</td> </tr>
104 </table>
105
106 <h2>How to use it</h2>
107
108 You can use ccache in two ways. The first is just to prefix your
109 compile commands with "ccache". For example, you could change the
110 "CC=gcc" line in your Makefile to be "CC=ccache gcc".<p>
111
112 Alternatively, you can create symbolic links from your compilers name
113 to ccache. This allows you to use ccache without any changes to your
114 build system.
115
116 <h2>Download</h2>
117
118 You can download the latest release from the <a
119 href="http://ccache.samba.org/ftp/ccache/">download directory</a>.<p>
120
121 For the bleeding edge, you can fetch ccache via CVS or
122 rsync. To fetch via cvs use the following command:
123
124 <pre>
125 cvs -d :pserver:cvs@pserver.samba.org:/cvsroot co ccache
126 </pre>
127
128 To fetch via rsync use this command:
129
130 <pre>
131 rsync -Pavz samba.org::ftp/unpacked/ccache .
132 </pre>
133
134 <h2>Related projects</h2>
135
136 Here are some related programs you may find interesting
137
138 <ul>
139 <li> <a href="http://distcc.samba.org/">distcc</a> - a distributed compilation system
140 <li> <a href="http://cachecc1.sourceforge.net/">cachecc1</a> - a gcc specific cache
141 <li> <a href="http://sourceforge.net/projects/gocache/">gocache</a> - a cross platform compiler cache
142 </ul>
143 <p>
144
145 <h2>Mailing list</h2>
146
147 <p>A <a href="http://lists.samba.org/mailman/listinfo/ccache/">mailing
148 list</a> is available for discussion of ccache.
149
150
151 <hr>
152 <tiny>
153 <a href="http://samba.org/~tridge/">Andrew Tridgell</a><br>
154 <a href="mailto:bugs@ccache.samba.org">bugs@ccache.samba.org</a>
155 </tiny>
156
157 </BODY>
158 </HTML>