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| author | Robin Murphy <robin.murphy@arm.com> | 2024-09-04 20:34:03 +0300 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2024-09-06 14:58:28 +0300 |
| commit | 4d5a7680f2b4d0c2955e1d9f9a594b050d637436 (patch) | |
| tree | 41275524b1b0f973d21eb5039a4a26099307a841 /Documentation/admin-guide/perf | |
| parent | abbe74dd105b45330dd269530060d30441d45b95 (diff) | |
| download | linux-4d5a7680f2b4d0c2955e1d9f9a594b050d637436.tar.xz | |
perf: Add driver for Arm NI-700 interconnect PMU
The Arm NI-700 Network-on-Chip Interconnect has a relatively
straightforward design with a hierarchy of voltage, power, and clock
domains, where each clock domain then contains a number of interface
units and a PMU which can monitor events thereon. As such, it begets a
relatively straightforward driver to interface those PMUs with perf.
Even more so than with arm-cmn, users will require detailed knowledge of
the wider system topology in order to meaningfully analyse anything,
since the interconnect itself cannot know what lies beyond the boundary
of each inscrutably-numbered interface. Given that, for now they are
also expected to refer to the NI-700 documentation for the relevant
event IDs to provide as well. An identifier is implemented so we can
come back and add jevents if anyone really wants to.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/9933058d0ab8138c78a61cd6852ea5d5ff48e393.1725470837.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'Documentation/admin-guide/perf')
| -rw-r--r-- | Documentation/admin-guide/perf/arm-ni.rst | 17 | ||||
| -rw-r--r-- | Documentation/admin-guide/perf/index.rst | 1 |
2 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/admin-guide/perf/arm-ni.rst b/Documentation/admin-guide/perf/arm-ni.rst new file mode 100644 index 000000000000..d26a8f697c36 --- /dev/null +++ b/Documentation/admin-guide/perf/arm-ni.rst @@ -0,0 +1,17 @@ +==================================== +Arm Network-on Chip Interconnect PMU +==================================== + +NI-700 and friends implement a distinct PMU for each clock domain within the +interconnect. Correspondingly, the driver exposes multiple PMU devices named +arm_ni_<x>_cd_<y>, where <x> is an (arbitrary) instance identifier and <y> is +the clock domain ID within that particular instance. If multiple NI instances +exist within a system, the PMU devices can be correlated with the underlying +hardware instance via sysfs parentage. + +Each PMU exposes base event aliases for the interface types present in its clock +domain. These require qualifying with the "eventid" and "nodeid" parameters +to specify the event code to count and the interface at which to count it +(per the configured hardware ID as reflected in the xxNI_NODE_INFO register). +The exception is the "cycles" alias for the PMU cycle counter, which is encoded +with the PMU node type and needs no further qualification. diff --git a/Documentation/admin-guide/perf/index.rst b/Documentation/admin-guide/perf/index.rst index 7eb3dcd6f4da..8502bc174640 100644 --- a/Documentation/admin-guide/perf/index.rst +++ b/Documentation/admin-guide/perf/index.rst @@ -16,6 +16,7 @@ Performance monitor support starfive_starlink_pmu arm-ccn arm-cmn + arm-ni xgene-pmu arm_dsu_pmu thunderx2-pmu |