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Diffstat (limited to 'Documentation/perf/arm_dsu_pmu.txt')
| -rw-r--r-- | Documentation/perf/arm_dsu_pmu.txt | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/perf/arm_dsu_pmu.txt b/Documentation/perf/arm_dsu_pmu.txt new file mode 100644 index 000000000000..d611e15f5add --- /dev/null +++ b/Documentation/perf/arm_dsu_pmu.txt @@ -0,0 +1,28 @@ +ARM DynamIQ Shared Unit (DSU) PMU +================================== + +ARM DynamIQ Shared Unit integrates one or more cores with an L3 memory system, +control logic and external interfaces to form a multicore cluster. The PMU +allows counting the various events related to the L3 cache, Snoop Control Unit +etc, using 32bit independent counters. It also provides a 64bit cycle counter. + +The PMU can only be accessed via CPU system registers and are common to the +cores connected to the same DSU. Like most of the other uncore PMUs, DSU +PMU doesn't support process specific events and cannot be used in sampling mode. + +The DSU provides a bitmap for a subset of implemented events via hardware +registers. There is no way for the driver to determine if the other events +are available or not. Hence the driver exposes only those events advertised +by the DSU, in "events" directory under : + + /sys/bus/event_sources/devices/arm_dsu_<N>/ + +The user should refer to the TRM of the product to figure out the supported events +and use the raw event code for the unlisted events. + +The driver also exposes the CPUs connected to the DSU instance in "associated_cpus". + + +e.g usage : + + perf stat -a -e arm_dsu_0/cycles/ |