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Diffstat (limited to 'doc/bitbake-user-manual/bitbake-user-manual-metadata.xml')
| -rw-r--r-- | doc/bitbake-user-manual/bitbake-user-manual-metadata.xml | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml b/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml index b4fc64e75..bc08c814d 100644 --- a/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml +++ b/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml @@ -1929,6 +1929,38 @@ not careful. </note> </para></listitem> + <listitem><para><emphasis><filename>[number_threads]</filename>:</emphasis> + Limits tasks to a specific number of simultaneous threads + during execution. + This varflag is useful when your build host has a large number + of cores but certain tasks need to be rate-limited due to various + kinds of resource constraints (e.g. to avoid network throttling). + <filename>number_threads</filename> works similarly to the + <link linkend='var-BB_NUMBER_THREADS'><filename>BB_NUMBER_THREADS</filename></link> + variable but is task-specific.</para> + + <para>Set the value globally. + For example, the following makes sure the + <filename>do_fetch</filename> task uses no more than two + simultaneous execution threads: + <literallayout class='monospaced'> + do_fetch[number_threads] = "2" + </literallayout> + <note><title>Warnings</title> + <itemizedlist> + <listitem><para> + Setting the varflag in individual recipes rather + than globally can result in unpredictable behavior. + </para></listitem> + <listitem><para> + Setting the varflag to a value greater than the + value used in the <filename>BB_NUMBER_THREADS</filename> + variable causes <filename>number_threads</filename> + to have no effect. + </para></listitem> + </itemizedlist> + </note> + </para></listitem> <listitem><para><emphasis><filename>[postfuncs]</filename>:</emphasis> List of functions to call after the completion of the task. </para></listitem> |