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diff --git a/Documentation/admin-guide/perf/thunderx2-pmu.rst b/Documentation/admin-guide/perf/thunderx2-pmu.rst new file mode 100644 index 000000000..01f158238 --- /dev/null +++ b/Documentation/admin-guide/perf/thunderx2-pmu.rst @@ -0,0 +1,44 @@ +============================================================= +Cavium ThunderX2 SoC Performance Monitoring Unit (PMU UNCORE) +============================================================= + +The ThunderX2 SoC PMU consists of independent, system-wide, per-socket +PMUs such as the Level 3 Cache (L3C), DDR4 Memory Controller (DMC) and +Cavium Coherent Processor Interconnect (CCPI2). + +The DMC has 8 interleaved channels and the L3C has 16 interleaved tiles. +Events are counted for the default channel (i.e. channel 0) and prorated +to the total number of channels/tiles. + +The DMC and L3C support up to 4 counters, while the CCPI2 supports up to 8 +counters. Counters are independently programmable to different events and +can be started and stopped individually. None of the counters support an +overflow interrupt. DMC and L3C counters are 32-bit and read every 2 seconds. +The CCPI2 counters are 64-bit and assumed not to overflow in normal operation. + +PMU UNCORE (perf) driver: + +The thunderx2_pmu driver registers per-socket perf PMUs for the DMC and +L3C devices. Each PMU can be used to count up to 4 (DMC/L3C) or up to 8 +(CCPI2) events simultaneously. The PMUs provide a description of their +available events and configuration options under sysfs, see +/sys/devices/uncore_<l3c_S/dmc_S/ccpi2_S/>; S is the socket id. + +The driver does not support sampling, therefore "perf record" will not +work. Per-task perf sessions are also not supported. + +Examples:: + + # perf stat -a -e uncore_dmc_0/cnt_cycles/ sleep 1 + + # perf stat -a -e \ + uncore_dmc_0/cnt_cycles/,\ + uncore_dmc_0/data_transfers/,\ + uncore_dmc_0/read_txns/,\ + uncore_dmc_0/write_txns/ sleep 1 + + # perf stat -a -e \ + uncore_l3c_0/read_request/,\ + uncore_l3c_0/read_hit/,\ + uncore_l3c_0/inv_request/,\ + uncore_l3c_0/inv_hit/ sleep 1 |