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.. _configure-stall-daemon-b38ece463e88:

======================
Configure stall daemon
======================

Stalld (stall daemon) is a program that monitors threads to protect critical
but low-scheduling-priority tasks from starvation. It is configured using
host-labels.

The supported host-labels are:

-   ``starlingx.io/stalld``

    supported values are: “enabled”, “disabled”

-   ``starlingx.io/stalld_cpu_functions``

    supported values are: “all”, “application”, “application-isolated”

Custom stalld labels are supported.

To enable stalld, run:

.. code-block:: none

    system host-label-assign <host> starlingx.io/stalld=enabled

To disable stalld, run:

.. code-block:: none

    system host-label-assign <host> starlingx.io/stalld=disabled

or

.. code-block:: none

    system host-label-remove <host> starlingx.io/stalld

Configure CPUs being monitored by Stalld
----------------------------------------

To have stalld monitor all CPUs.

.. code-block:: none

    system host-label-assign <host> starlingx.io/stalld_cpu_functions=all

To have stalld monitor all application CPUs.

.. note::

    This also includes application-isolated CPUs.

.. code-block:: none

    system host-label-assign <host> starlingx.io/stalld_cpu_functions=application

To have stalld monitor only application-isolated CPUs.

.. code-block:: none

    system host-label-assign <host> starlingx.io/stalld_cpu_functions=application-isolated

Stalld can be configured with |eBPF| backend, reducing CPU usage on larger
systems.

.. code-block:: none

    system host-label-assign <node> starlingx.io/stalld.backend=queue_track


Configure Custom Stalld Parameters
----------------------------------

You can specify custom parameters that are passed as startup arguments to
stalld. The parameters are specified in the following format:

``system host-label assign <node> starlingx.io/stalld.xxxx=yyyy``

which becomes ``stalld --xxxx=yyyy``

``system host-label assign <node> starlingx.io/stalld.zzzz=''``

which becomes ``stalld --zzzz``

Some examples:

``system host-label assign controller-0``

``starlingx.io/stalld.boost_period=1000000000``

``starlingx.io/stalld.boost_runtime=20000``

``starlingx.io/stalld.boost_duration=1``

``starlingx.io/stalld.starving_threshold=2``

``starlingx.io/stalld.verbose=''``

``starlings.io/stalld.log_kmsg=''``

``starlingx.io/stalld.force_fifo=''``