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| author |   Scott Rifenbark <srifenbark@gmail.com> | 2015-10-27 09:15:10 -0700 |
|---|---|---|
| committer |   Richard Purdie <richard.purdie@linuxfoundation.org> | 2015-10-29 07:35:19 +0000 |
| commit | 4e0da1ef4a58a7ba4b92d4e07ef79cf7bd90abf0 (patch) | |
| tree | e696019676e91683dfeedcb82735020f343ead50 | |
| parent | 0f0c205b9d6c24bee334eabb359973e0368ce931 (diff) | |
| download | bitbake-4e0da1ef4a58a7ba4b92d4e07ef79cf7bd90abf0.tar.gz | |
bitbake-user-manual: Added new description for BB_TASK_IONICE_LEVEL
Added a new variable description here for this variable.
Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
| -rw-r--r-- | doc/bitbake-user-manual/bitbake-user-manual-ref-variables.xml | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.xml b/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.xml index 9e4551be1..e5aeffcff 100644 --- a/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.xml +++ b/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.xml @@ -856,6 +856,56 @@ </glossdef> </glossentry> + <glossentry id='var-BB_TASK_IONICE_LEVEL'><glossterm>BB_TASK_IONICE_LEVEL</glossterm> + <glossdef> + <para> + Allows adjustment of a task's Input/Output priority. + During Autobuilder testing, random failures can occur + for tasks due to I/O starvation. + These failures occur during various QEMU runtime timeouts. + You can use the <filename>BB_TASK_IONICE_LEVEL</filename> + variable to adjust the I/O priority of these tasks. + <note> + This variable works similarly to the + <link linkend='var-BB_TASK_NICE_LEVEL'><filename>BB_TASK_NICE_LEVEL</filename></link> + variable except with a task's I/O priorities. + </note> + </para> + + <para> + Set the variable as follows: + <literallayout class='monospaced'> + BB_TASK_IONICE_LEVEL = "<replaceable>class</replaceable>.<replaceable>prio</replaceable>" + </literallayout> + For <replaceable>class</replaceable>, the default value is + "2", which is a best effort. + You can use "1" for realtime and "3" for idle. + If you want to use realtime, you must have superuser + privileges. + </para> + + <para> + For <replaceable>prio</replaceable>, you can use any + value from "0", which is the highest priority, to "7", + which is the lowest. + The default value is "4". + You do not need any special privileges to use this range + of priority values. + <note> + In order for your I/O priority settings to take effect, + you need the Completely Fair Queuing (CFQ) Scheduler + selected for the backing block device. + To select the scheduler, use the following command form + where <replaceable>device</replaceable> is the device + (e.g. sda, sdb, and so forth): + <literallayout class='monospaced'> + $ sudo sh -c “echo cfq > /sys/block/<replaceable>device</replaceable>/queu/scheduler + </literallayout> + </note> + </para> + </glossdef> + </glossentry> + <glossentry id='var-BB_TASK_NICE_LEVEL'><glossterm>BB_TASK_NICE_LEVEL</glossterm> <glossdef> <para> |