[PATCH] perf/arm-cmn: Add documentation for nodeid
From: Zidenberg, Tsahi <hidden>
Date: 2020-10-05 13:37:31
Subsystem:
arm interconnect pmu drivers, documentation, the rest · Maintainers:
Robin Murphy, Jonathan Corbet, Linus Torvalds
Document how nodeids could be calculated. Signed-off-by: Tzachi Zidenberg <redacted> --- Documentation/admin-guide/perf/arm-cmn.rst | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/perf/arm-cmn.rst b/Documentation/admin-guide/perf/arm-cmn.rst
index 0e4809346014..a68f26531e4a 100644
--- a/Documentation/admin-guide/perf/arm-cmn.rst
+++ b/Documentation/admin-guide/perf/arm-cmn.rst@@ -41,8 +41,14 @@ specified by "occupid".
By default each event provides an aggregate count over all nodes of the given type. To target a specific node, "bynodeid" must be set to 1 and -"nodeid" to the appropriate value derived from the CMN configuration -(as defined in the "Node ID Mapping" section of the TRM). +"nodeid" to the appropriate value derived from the CMN configuration. + +The CMN map is written to /sys/kernel/debug/arm-cmn/map. +A nodeid could be calculated with this formulae: + node-id = d | (p << 2) | (y << 3) | (x << (3 + xybits)) +where: + x,y,p,d are node location as can be seen in the map + xybits is 2 for meshes <= 2*2, and 3 otherwise. Watchpoints ----------- -- 2.16.5 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel