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- StarFive StarLink Performance Monitor Unit (PMU)
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- StarFive StarLink Performance Monitor Unit (PMU) exists within the
- StarLink Coherent Network on Chip (CNoC) that connects multiple CPU
- clusters with an L3 memory system.
- The uncore PMU supports overflow interrupt, up to 16 programmable 64bit
- event counters, and an independent 64bit cycle counter.
- The PMU can only be accessed via Memory Mapped I/O and are common to the
- cores connected to the same PMU.
- Driver exposes supported PMU events in sysfs "events" directory under::
- /sys/bus/event_source/devices/starfive_starlink_pmu/events/
- Driver exposes cpu used to handle PMU events in sysfs "cpumask" directory
- under::
- /sys/bus/event_source/devices/starfive_starlink_pmu/cpumask/
- Driver describes the format of config (event ID) in sysfs "format" directory
- under::
- /sys/bus/event_source/devices/starfive_starlink_pmu/format/
- Example of perf usage::
- $ perf list
- starfive_starlink_pmu/cycles/ [Kernel PMU event]
- starfive_starlink_pmu/read_hit/ [Kernel PMU event]
- starfive_starlink_pmu/read_miss/ [Kernel PMU event]
- starfive_starlink_pmu/read_request/ [Kernel PMU event]
- starfive_starlink_pmu/release_request/ [Kernel PMU event]
- starfive_starlink_pmu/write_hit/ [Kernel PMU event]
- starfive_starlink_pmu/write_miss/ [Kernel PMU event]
- starfive_starlink_pmu/write_request/ [Kernel PMU event]
- starfive_starlink_pmu/writeback/ [Kernel PMU event]
- $ perf stat -a -e /starfive_starlink_pmu/cycles/ sleep 1
- Sampling is not supported. As a result, "perf record" is not supported.
- Attaching to a task is not supported, only system-wide counting is supported.
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