From 62a67c813a9fe7e3c3fef6f5dda2d1699af55c69 Mon Sep 17 00:00:00 2001 From: Scott Rifenbark Date: Thu, 9 Oct 2014 14:34:47 -0700 Subject: ref-manual: WIP - New section on speeding up builds. Fixes [YOCTO #5594] (From yocto-docs rev: e841f3c59f0c272f8a7314b2de20bab6581149cd) Signed-off-by: Scott Rifenbark Signed-off-by: Richard Purdie --- documentation/ref-manual/usingpoky.xml | 139 +++++++++++++++++++++++++++++++++ 1 file changed, 139 insertions(+) (limited to 'documentation/ref-manual') diff --git a/documentation/ref-manual/usingpoky.xml b/documentation/ref-manual/usingpoky.xml index 1a211ca78a..030448df0b 100644 --- a/documentation/ref-manual/usingpoky.xml +++ b/documentation/ref-manual/usingpoky.xml @@ -89,6 +89,145 @@ +
+ Speeding Up the Build + + + Build time can be an issue. + By default, the build system uses three simple controls to try and + maximize build efficiency: + + + BB_NUMBER_THREADS + + + BB_NUMBER_PARSE_THREADS + + + PARALLEL_MAKE + + + These three variables all scale to the number of processor cores + available on the build system. + This auto-scaling ensures that the build system fundamentally takes + advantage of potential parallel operations during the build + based on the build machine's capabilities. + + + + If you need to achieve even faster builds than what the build system + produces by default, you can consider and implement some of the + following: + + + BB_NUMBER_THREADS, + BB_NUMBER_PARSE_THREADS, and + PARALLEL_MAKE: + As previously mentioned, the build system scales the values + for these variables. + However, you can manually override them in your + local.conf file if you are not satisfied + with the defaults. + + + File system type: + The file system type that the build is being performed on can + also influence performance. + Using ext4 is recommended as compared + to ext2 and ext3 + due to ext4 improved features + such as extents. + + + Disabling the updating of access time using + noatime: + The noatime mount option prevents the + build system from updating file and directory access times. + + + Setting a longer commit: + Richard - I need some sort of general summary here about this. + I don't know the context. + + + The packaging backend: + Of the available packaging backends, IPK is the fastest. + Additionally, selecting a singular packaging backend also + helps. + + + Using /tmp as a temporary file system: + While this can help speed up the build, the benefits are + limited due to the compiler using + -pipe. + The build system goes to some lengths to avoid + sync() calls into the + file system on the principle that if there was a significant + failure, the + Build Directory + contents could easily be rebuilt. + + + Inheriting the + rm_work + class: + Inheriting this class has shown to speed up builds due to + significantly lower amounts of data stored in the data + cache as well as on disk. + Inheriting this class also makes cleanup of + TMPDIR + faster, at the expense of being easily able to dive into the + source code. + File system maintainers have recommended that the fastest way + to clean up large numbers of files is to reformat partitions + rather than delete files due to the linear nature of partitions. + This, of course, assumes you structure the disk partitions and + file systems in a way that this is practical. + + + Aside from the previous list, you should keep some trade offs in + mind that can help you speed up the build: + + + Exclude debug symbols and other debug information: + If you do not need these symbols and other debug information, + disabling the *-dbg package generation + can speed up the build. + You can disable this generation by setting the + INHIBIT_PACKAGE_DEBUG_SPLIT + variable to "1". + + + Disable static library generation for recipes derived from + autoconf or libtool: + Following is an example showing how to disable static + libraries and still provide an override to handle exceptions: + + STATICLIBCONF = "--disable-static" + STATICLIBCONF_sqlite3-native = "" + EXTRA_OECONF += "${STATICLIBCONF}" + + Notes + + + Some recipes need static libraries in order to work + correctly (e.g. pseudo-native + needs sqlite3-native). + Overrides, as in the previous example, account for + these kinds of exceptions. + + + Some packages have packaging code that assumes the + presence of the static libraries. + If so, you might need to exclude them as well. + + + + + + +
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Installing and Using the Result -- cgit v1.2.3-54-g00ecf