docs: update userguide with new option for intel_pmu plugin

Update the userguide for intel_pmu with new "Cores"
option available in plugin configuration.
Added sample config with default configuration.

Change-Id: Ibe4d451131dc2c9ae0282f018c7e23596f4bf2c1
Signed-off-by: Kamil Wiatrowski <kamilx.wiatrowski@intel.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/docs/release/userguide/feature.userguide.rst b/docs/release/userguide/feature.userguide.rst
index 55a248b9..eeec7a2e 100644
--- a/docs/release/userguide/feature.userguide.rst
+++ b/docs/release/userguide/feature.userguide.rst
@@ -413,6 +413,7 @@ include:
       ReportHardwareCacheEvents true
       ReportKernelPMUEvents true
       ReportSoftwareEvents true
+      Cores ""
     </Plugin>
 
 If you want to monitor Intel CPU specific CPU events, make sure to enable the
@@ -426,12 +427,21 @@ additional two options shown below:
      ReportSoftwareEvents true
      EventList "$HOME/.cache/pmu-events/GenuineIntel-6-2D-core.json"
      HardwareEvents "L2_RQSTS.CODE_RD_HIT,L2_RQSTS.CODE_RD_MISS" "L2_RQSTS.ALL_CODE_RD"
+     Cores ""
     </Plugin>
 
 .. note::
     If you set XDG_CACHE_HOME to anything other than the variable above - you will need to modify
     the path for the EventList configuration.
 
+Use "Cores" option to monitor metrics only for configured cores. If an empty string is provided
+as value for this field default cores configuration is applied - that is all available cores
+are monitored separately. To limit monitoring to cores 0-7 set the option as shown below:
+
+.. code:: bash
+
+    Cores "[0-7]"
+
 For more information on the plugin parameters, please see:
 https://github.com/collectd/collectd/blob/master/src/collectd.conf.pod