docs: Document memory bandwidth allocation limits more clearly

The meaning of the values as well as their maximums are hard to predict
and accounting for all the possibilities (which by the way might change
during daemon's execution) is borderline hallucinatory.  There is
already a way we represent them, which is the same as the Linux kernel.
We do not interpret them at all, just blindly use them.  In order to
make this more apparent for the users change the documentation for the
<memorytune/> (not <memtune/>) element more boldly.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index 2b0b81040b38bc20623dae737862baffa2592d09..4336cff3ac05ca7c29839dfd8dc018e7b5ccfdf4 100644 (file)
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -1018,8 +1018,11 @@ CPU Tuning
       ``id``
          Host node id from which to allocate memory bandwidth.
       ``bandwidth``
-         The memory bandwidth to allocate from this node. The value by default
-         is in percentage.
+         The memory bandwidth to allocate from this node. The value is usually
+         in percent (Intel) but can also be in MB/s (if resctrl is mounted with
+         the ``mba_MBps`` option) or in 1/8 GB/s increments (AMD).  The user is
+         responsible for making sure the value makes sense on their system and
+         configuration.
 
 
 Memory Allocation