thunderx2-pmu.rst 1.8 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344
  1. =============================================================
  2. Cavium ThunderX2 SoC Performance Monitoring Unit (PMU UNCORE)
  3. =============================================================
  4. The ThunderX2 SoC PMU consists of independent, system-wide, per-socket
  5. PMUs such as the Level 3 Cache (L3C), DDR4 Memory Controller (DMC) and
  6. Cavium Coherent Processor Interconnect (CCPI2).
  7. The DMC has 8 interleaved channels and the L3C has 16 interleaved tiles.
  8. Events are counted for the default channel (i.e. channel 0) and prorated
  9. to the total number of channels/tiles.
  10. The DMC and L3C support up to 4 counters, while the CCPI2 supports up to 8
  11. counters. Counters are independently programmable to different events and
  12. can be started and stopped individually. None of the counters support an
  13. overflow interrupt. DMC and L3C counters are 32-bit and read every 2 seconds.
  14. The CCPI2 counters are 64-bit and assumed not to overflow in normal operation.
  15. PMU UNCORE (perf) driver:
  16. The thunderx2_pmu driver registers per-socket perf PMUs for the DMC and
  17. L3C devices. Each PMU can be used to count up to 4 (DMC/L3C) or up to 8
  18. (CCPI2) events simultaneously. The PMUs provide a description of their
  19. available events and configuration options under sysfs, see
  20. /sys/bus/event_source/devices/uncore_<l3c_S/dmc_S/ccpi2_S/>; S is the socket id.
  21. The driver does not support sampling, therefore "perf record" will not
  22. work. Per-task perf sessions are also not supported.
  23. Examples::
  24. # perf stat -a -e uncore_dmc_0/cnt_cycles/ sleep 1
  25. # perf stat -a -e \
  26. uncore_dmc_0/cnt_cycles/,\
  27. uncore_dmc_0/data_transfers/,\
  28. uncore_dmc_0/read_txns/,\
  29. uncore_dmc_0/write_txns/ sleep 1
  30. # perf stat -a -e \
  31. uncore_l3c_0/read_request/,\
  32. uncore_l3c_0/read_hit/,\
  33. uncore_l3c_0/inv_request/,\
  34. uncore_l3c_0/inv_hit/ sleep 1