1 files changed, 69 insertions, 6 deletions

diff --git a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.rst b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.rst
index 477443e228..6be8dbbf63 100644
--- a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.rst
+++ b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-ref-variables.rst
@@ -310,6 +310,11 @@ overview of their function and contents.
 
       For example usage, see :term:`BB_GIT_SHALLOW`.
 
+   :term:`BB_GIT_DEFAULT_DESTSUFFIX`
+      The default destination directory where the Git fetcher unpacks the
+      source code. If this variable is not set, the source code is unpacked in a
+      directory named "git".
+
    :term:`BB_GIT_SHALLOW`
       Setting this variable to "1" enables the support for fetching, using and
       generating mirror tarballs of `shallow git repositories <https://riptutorial.com/git/example/4584/shallow-clone>`_.
@@ -533,11 +538,28 @@ overview of their function and contents.
       version 4.20 expose under ``/proc/pressure``. The threshold represents
       the difference in "total" pressure from the previous second. The
       minimum value is 1.0 (extremely slow builds) and the maximum is
-      1000000 (a pressure value unlikely to ever be reached).
+      1000000 (a pressure value unlikely to ever be reached). See
+      https://docs.kernel.org/accounting/psi.html for more information.
+
+      A default value to limit the CPU pressure to be set in ``conf/local.conf``
+      could be::
+
+         BB_PRESSURE_MAX_CPU = "15000"
+
+      Multiple values should be tested on the build host to determine what suits
+      best, depending on the need for performances versus load average during
+      the build.
+
+      .. note::
 
-      This threshold can be set in ``conf/local.conf`` as::
+         You may see numerous messages printed by BitBake in the case the
+         :term:`BB_PRESSURE_MAX_CPU` is too low:
 
-         BB_PRESSURE_MAX_CPU = "500"
+            Pressure status changed to CPU: True, IO: False, Mem: False (CPU: 1105.9/2.0, IO: 0.0/2.0, Mem: 0.0/2.0) - using 1/64 bitbake threads
+
+         This means that the :term:`BB_PRESSURE_MAX_CPU` should be increased to
+         a reasonable value for limiting the CPU pressure on the system.
+         Monitor the varying value after ``IO:`` above to set a sensible value.
 
    :term:`BB_PRESSURE_MAX_IO`
       Specifies a maximum I/O pressure threshold, above which BitBake's
@@ -549,14 +571,34 @@ overview of their function and contents.
       version 4.20 expose under ``/proc/pressure``. The threshold represents
       the difference in "total" pressure from the previous second. The
       minimum value is 1.0 (extremely slow builds) and the maximum is
-      1000000 (a pressure value unlikely to ever be reached).
+      1000000 (a pressure value unlikely to ever be reached). See
+      https://docs.kernel.org/accounting/psi.html for more information.
 
       At this point in time, experiments show that IO pressure tends to
       be short-lived and regulating just the CPU with
       :term:`BB_PRESSURE_MAX_CPU` can help to reduce it.
 
-   :term:`BB_PRESSURE_MAX_MEMORY`
+      A default value to limit the IO pressure to be set in ``conf/local.conf``
+      could be::
+
+         BB_PRESSURE_MAX_IO = "15000"
+
+      Multiple values should be tested on the build host to determine what suits
+      best, depending on the need for performances versus I/O usage during the
+      build.
+
+      .. note::
 
+         You may see numerous messages printed by BitBake in the case the
+         :term:`BB_PRESSURE_MAX_IO` is too low::
+
+            Pressure status changed to CPU: None, IO: True, Mem: False (CPU: 2236.0/None, IO: 153.6/2.0, Mem: 0.0/2.0) - using 19/64 bitbake threads
+
+         This means that the :term:`BB_PRESSURE_MAX_IO` should be increased to
+         a reasonable value for limiting the I/O pressure on the system.
+         Monitor the varying value after ``IO:`` above to set a sensible value.
+
+   :term:`BB_PRESSURE_MAX_MEMORY`
       Specifies a maximum memory pressure threshold, above which BitBake's
       scheduler will not start new tasks (providing there is at least
       one active task). If no value is set, memory pressure is not
@@ -566,7 +608,8 @@ overview of their function and contents.
       version 4.20 expose under ``/proc/pressure``. The threshold represents
       the difference in "total" pressure from the previous second. The
       minimum value is 1.0 (extremely slow builds) and the maximum is
-      1000000 (a pressure value unlikely to ever be reached).
+      1000000 (a pressure value unlikely to ever be reached). See
+      https://docs.kernel.org/accounting/psi.html for more information.
 
       Memory pressure is experienced when time is spent swapping,
       refaulting pages from the page cache or performing direct reclaim.
@@ -574,6 +617,26 @@ overview of their function and contents.
       might be useful as a last resort to prevent OOM errors if they are
       occurring during builds.
 
+      A default value to limit the memory pressure to be set in
+      ``conf/local.conf`` could be::
+
+         BB_PRESSURE_MAX_MEMORY = "15000"
+
+      Multiple values should be tested on the build host to determine what suits
+      best, depending on the need for performances versus memory consumption
+      during the build.
+
+      .. note::
+
+         You may see numerous messages printed by BitBake in the case the
+         :term:`BB_PRESSURE_MAX_MEMORY` is too low::
+
+            Pressure status changed to CPU: None, IO: False, Mem: True (CPU: 29.5/None, IO: 0.0/2.0, Mem: 2553.3/2.0) - using 17/64 bitbake threads
+
+         This means that the :term:`BB_PRESSURE_MAX_MEMORY` should be increased to
+         a reasonable value for limiting the memory pressure on the system.
+         Monitor the varying value after ``Mem:`` above to set a sensible value.
+
    :term:`BB_RUNFMT`
       Specifies the name of the executable script files (i.e. run files)
       saved into ``${``\ :term:`T`\ ``}``. By default, the