[dpdk-dev] [v4 3/3] doc: update vm_power_manager cmdline options in doc
Rory Sexton
rory.sexton at intel.com
Tue Jul 14 18:02:00 CEST 2020
Updating the vm_power_manager docs to reflect changes made in
previous patches in set.
Signed-off-by: Rory Sexton <rory.sexton at intel.com>
Reviewed-by: David Hunt <david.hunt at intel.com>
---
v4: no changes
---
doc/guides/sample_app_ug/vm_power_management.rst | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/doc/guides/sample_app_ug/vm_power_management.rst b/doc/guides/sample_app_ug/vm_power_management.rst
index e98277ccb..1b6de8e93 100644
--- a/doc/guides/sample_app_ug/vm_power_management.rst
+++ b/doc/guides/sample_app_ug/vm_power_management.rst
@@ -410,19 +410,21 @@ There are a couple of command line parameters for enabling the out-of-band
monitoring of branch ratios on cores doing busy polling using PMDs as
described below:
-``--core-list {list of cores}``
+``--core-branch-ratio {list of cores}:{branch ratio for listed cores}``
Specify the list of cores to monitor the ratio of branch misses
to branch hits. A tightly-polling PMD thread has a very low
branch ratio, therefore the core frequency scales down to the
minimum allowed value. On receiving packets, the code path changes,
causing the branch ratio to increase. When the ratio goes above
the ratio threshold, the core frequency scales up to the maximum
- allowed value.
-
-``--branch-ratio {ratio}``
- Specify a floating-point number that identifies the threshold at which
- to scale up or down for the given workload. The default branch ratio
- is 0.01 and needs adjustment for different workloads.
+ allowed value. The specified branch-ratio is a floating point number
+ that identifies the threshold at which to scale up or down for the
+ elements of the core-list. If not included the default branch ratio of
+ 0.01 but will need adjustment for different workloads
+
+ This parameter can be used multiple times for different sets of cores.
+ The branch ratio mechanism can also be useful for non-PMD cores and
+ hyper-threaded environments where C-States are disabled.
Compiling and Running the Guest Applications
--
2.25.1
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