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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. |
