diff --git a/documentation/ref-manual/usingpoky.xml b/documentation/ref-manual/usingpoky.xml
index a7bff18b01..e2e05b2514 100644
--- a/documentation/ref-manual/usingpoky.xml
+++ b/documentation/ref-manual/usingpoky.xml
@@ -914,42 +914,51 @@
Build time can be an issue.
- By default, the build system uses three simple controls to try and
- maximize build efficiency:
+ By default, the build system uses simple controls to try and maximize
+ build efficiency.
+ In general, the default settings for all the following variables
+ result in the most efficient build times when dealing with single
+ socket systems (i.e. a single CPU).
+ If you have multiple CPUs, you might try increasing the default
+ values to gain more speed.
+ See the descriptions in the glossary for each variable for more
+ information:
- BB_NUMBER_THREADS
+ BB_NUMBER_THREADS:
+ The maximum number of threads BitBake simultaneously executes.
- BB_NUMBER_PARSE_THREADS
+ BB_NUMBER_PARSE_THREADS:
+ The number of threads BitBake uses during parsing.
- PARALLEL_MAKE
+ PARALLEL_MAKE:
+ Extra options passed to the make command
+ during the
+ do_compile
+ task in order to specify parallel compilation on the
+ local build host.
+
+
+ PARALLEL_MAKEINST:
+ Extra options passed to the make command
+ during the
+ do_install
+ task in order to specify parallel installation on the
+ local build host.
- 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.
+ As mentioned, these variables all scale to the number of processor
+ cores available on the build system.
+ For single socket systems, 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:
+ Following are additional factors that can affect build speed:
-
- BB_NUMBER_THREADS,
- BB_NUMBER_PARSE_THREADS, and
- PARALLEL_MAKE:
- As previously mentioned, the build system scales the values
- for these variables so you should probably not override
- these to try to speed up a build.
- However, for completeness regarding this list, it is worth
- mentioning that you can manually override these variables
- by setting them in your local.conf file.
-
File system type:
The file system type that the build is being performed on can
@@ -981,7 +990,9 @@
helps.
- Using /tmp as a temporary file system:
+ Using tmpfs for
+ TMPDIR
+ as a temporary file system:
While this can help speed up the build, the benefits are
limited due to the compiler using
-pipe.
@@ -1013,6 +1024,11 @@
Aside from the previous list, you should keep some trade offs in
mind that can help you speed up the build:
+
+ Remove items from
+ DISTRO_FEATURES
+ that you might not need.
+
Exclude debug symbols and other debug information:
If you do not need these symbols and other debug information,