ref-manual: Added the buildstats class.

(From yocto-docs rev: 72eb0af4511b2837d3178cc109706f57412e8f59)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 31 insertions, 1 deletions

diff --git a/documentation/ref-manual/ref-classes.xml b/documentation/ref-manual/ref-classes.xml
index cab546a0ae..e8f5a2f72b 100644
--- a/documentation/ref-manual/ref-classes.xml
+++ b/documentation/ref-manual/ref-classes.xml
@@ -332,12 +332,42 @@
         The Build History (<filename>buildhistory</filename>) class records a
         history of build output metadata, which can be used to detect possible
         regressions as well as used for analysis of the build output.
-        For more information on usinig Build History, see the
+        For more information on using Build History, see the
         "<link linkend='maintaining-build-output-quality'>Maintaining Build Output Quality</link>"
         section.
     </para>
 </section>
 
+<section id='ref-classes-buildstats'>
+    <title><filename>buildstats.bbclass</filename></title>
+
+    <para>
+        The Build Stats (<filename>buildstats</filename>) class records
+        performance statistics about each task executed during the build
+        (e.g. elapsed time, CPU usage, and I/O usage).
+    </para>
+
+    <para>
+        When you use this class, the output goes into the
+        <link linkend='var-BUILDSTATS_BASE'><filename>BUILDSTATS_BASE</filename></link>
+        directory, which defaults to <filename>${TMPDIR}/buildstats/</filename>.
+        You can analyze the elapsed time using
+        <filename>scripts/pybootchartgui/pybootchartgui.py</filename>, which
+        produces a cascading chart of the entire build process and can be
+        useful for highlighting bottlenecks.
+    </para>
+
+    <para>
+        To enable this class, use the
+        <link linkend='var-USER_CLASSES'><filename>USER_CLASSES</filename></link>
+        variable from your <filename>local.conf</filename> file.
+        The <filename>meta-yocto/conf/local.conf.sample</filename> file
+        in the
+        <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>
+        enables this class by default.
+    </para>
+</section>
+
 <section id='ref-classes-debian'>
     <title>Debian Renaming - <filename>debian.bbclass</filename></title>