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1================================================2StarFive StarLink Performance Monitor Unit (PMU)3================================================4 5StarFive StarLink Performance Monitor Unit (PMU) exists within the6StarLink Coherent Network on Chip (CNoC) that connects multiple CPU7clusters with an L3 memory system.8 9The uncore PMU supports overflow interrupt, up to 16 programmable 64bit10event counters, and an independent 64bit cycle counter.11The PMU can only be accessed via Memory Mapped I/O and are common to the12cores connected to the same PMU.13 14Driver exposes supported PMU events in sysfs "events" directory under::15 16 /sys/bus/event_source/devices/starfive_starlink_pmu/events/17 18Driver exposes cpu used to handle PMU events in sysfs "cpumask" directory19under::20 21 /sys/bus/event_source/devices/starfive_starlink_pmu/cpumask/22 23Driver describes the format of config (event ID) in sysfs "format" directory24under::25 26 /sys/bus/event_source/devices/starfive_starlink_pmu/format/27 28Example of perf usage::29 30 $ perf list31 32 starfive_starlink_pmu/cycles/ [Kernel PMU event]33 starfive_starlink_pmu/read_hit/ [Kernel PMU event]34 starfive_starlink_pmu/read_miss/ [Kernel PMU event]35 starfive_starlink_pmu/read_request/ [Kernel PMU event]36 starfive_starlink_pmu/release_request/ [Kernel PMU event]37 starfive_starlink_pmu/write_hit/ [Kernel PMU event]38 starfive_starlink_pmu/write_miss/ [Kernel PMU event]39 starfive_starlink_pmu/write_request/ [Kernel PMU event]40 starfive_starlink_pmu/writeback/ [Kernel PMU event]41 42 43 $ perf stat -a -e /starfive_starlink_pmu/cycles/ sleep 144 45Sampling is not supported. As a result, "perf record" is not supported.46Attaching to a task is not supported, only system-wide counting is supported.47