From c014281f72f4f54ec8e681ef2b8e1080de9ab5cf Mon Sep 17 00:00:00 2001 From: Aryaman Gupta Date: Mon, 19 Sep 2022 16:58:12 +0200 Subject: doc: bitbake-user-manual: Add definition for BB_PRESSURE_MAX variables Add the definitions for the BB_PRESSURE_MAX{CPU|IO|MEMORY} variables in the bitbake varibales glossary. Further information on how to determine a good threshold will be added to the Yocto reference manual in a later commit. Signed-off-by: Aryaman Gupta Signed-off-by: Randy Macleod Signed-off-by: Michael Opdenacker Reviewed-by: Michael Opdenacker Reviewed-by: Quentin Schulz Signed-off-by: Richard Purdie --- .../bitbake-user-manual-ref-variables.rst | 25 ++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.rst b/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.rst index 12aef3cbb..725e6c2cd 100644 --- a/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.rst +++ b/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.rst @@ -483,6 +483,31 @@ overview of their function and contents. You must set this variable in the external environment in order for it to work. + :term:`BB_PRESSURE_MAX_CPU` + The threshold for maximum CPU pressure before BitBake prevents the + scheduling of new tasks. Once the :term:`BB_PRESSURE_MAX_CPU` threshold + is exceeded, new tasks are not started until the pressure subsides to + below the threshold. If :term:`BB_PRESSURE_MAX_CPU` is not set, CPU + pressure is not monitored. A threshold can be set in ``conf/local.conf`` + as:: + + BB_PRESSURE_MAX_CPU = "500" + + :term:`BB_PRESSURE_MAX_IO` + The threshold for maximum IO pressure experienced before BitBake + prevents the scheduling of new tasks. The IO pressure is regulated in the + same way as :term:`BB_PRESSURE_MAX_CPU`. At this point in time, + experiments show that IO pressure tends to be short-lived and regulating + just the CPU can help to reduce it. + + :term:`BB_PRESSURE_MAX_MEMORY` + The threshold for maximum memory pressure experienced before BitBake + prevents the scheduling of new tasks. The memory pressure is regulated in + the same way as :term:`BB_PRESSURE_MAX_CPU`. Note that any memory + pressure indicates that a system is being pushed beyond its capacity. At + this point in time, experiments show that memory pressure tends to be + short-lived and regulating just the CPU can help to reduce it. + :term:`BB_RUNFMT` Specifies the name of the executable script files (i.e. run files) saved into ``${``\ :term:`T`\ ``}``. By default, the -- cgit 1.2.3-korg