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Disable nohz_full in standard kernels

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Updated the procedure ~(keystone)admin)$ system host-unlock <worker> and updated information about Standard Systems.

Minor updates (rewrited a sentence and corrected spelling error.

Created a sub-section to add the Disable nohz_full label step-by-step.

Signed-off-by: Elaine Fonaro <elaine.fonaro@windriver.com>
Change-Id: I7999a17cd21d3ed73ef58a25ffd727ce245e7233
This commit is contained in:
Elaine Fonaro 2022-06-10 16:29:28 -03:00 committed by Juanita-Balaraj
parent 72b67d3d14
commit e9eb92e888
1 changed files with 42 additions and 0 deletions
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doc/source/admintasks/kubernetes/isolating-cpu-cores-to-enhance-application-performance.rst
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@ -76,3 +76,45 @@ running :command:`sched_getaffinity()` command, or by parsing
Isolated CPUs can be identified in the container by looking for files such as
``/dev/cpu/<X>`` where ``<X>`` is a number, or by referencing
``/sys/devices/system/cpu/isolated`` against the CPUs associated with this container.
-------------------------------------
Isolating CPU Cores from Kernel Noise
-------------------------------------
For better performance of latency-sensitive applications, and to improve energy
efficiency on idle CPUs, it is possible to isolate CPU cores from kernel noise
with the ``nohz_full`` kernel parameter. This configuration is supported in both
low-latency and standard kernel types. However, for standard kernels, it is
possible to disable the CPU isolation by assigning a label to the target host
with worker sub function.
To summarize, the configuration is supported by default in workers of any
kernel type, but for standard kernels, you can enable the ``disable-nohz-full``
label to disable it.
Use the procedure below to disable the ``nohz_full`` parameter on standard
kernels:
.. rubric:: |proc|
#. Lock the host.
.. code-block:: none
~(keystone)admin)$ system host-lock <worker>
#. Assign the ``disable-nohz-full`` label.
.. code-block:: none
~(keystone)admin)$ system host-label-assign <worker> disable-nohz-full=enabled
#. Unlock the host.
.. code-block:: none
~(keystone)admin)$ system host-unlock <worker>
.. note::
``disable-nohz-full`` label can be also assigned via the GUI.