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Diffstat (limited to 'Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst')
| -rw-r--r-- | Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst b/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst index c065764d41fe..9945c43f6a7a 100644 --- a/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst +++ b/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst @@ -8,6 +8,7 @@ metrics like memory bandwidth, latency, and utilization: * Unified Coherence Fabric (UCF) * PCIE * PCIE-TGT +* CPU Memory (CMEM) Latency PMU Driver ---------- @@ -344,3 +345,27 @@ Example usage: 0x10000 to 0x100FF on socket 0's PCIE RC-1:: perf stat -a -e nvidia_pcie_tgt_pmu_0_rc_1/event=0x1,dst_addr_base=0x10000,dst_addr_mask=0xFFF00,dst_addr_en=0x1/ + +CPU Memory (CMEM) Latency PMU +----------------------------- + +This PMU monitors latency events of memory read requests from the edge of the +Unified Coherence Fabric (UCF) to local CPU DRAM: + + * RD_REQ counters: count read requests (32B per request). + * RD_CUM_OUTS counters: accumulated outstanding request counter, which track + how many cycles the read requests are in flight. + * CYCLES counter: counts the number of elapsed cycles. + +The average latency is calculated as:: + + FREQ_IN_GHZ = CYCLES / ELAPSED_TIME_IN_NS + AVG_LATENCY_IN_CYCLES = RD_CUM_OUTS / RD_REQ + AVERAGE_LATENCY_IN_NS = AVG_LATENCY_IN_CYCLES / FREQ_IN_GHZ + +The events and configuration options of this PMU device are described in sysfs, +see /sys/bus/event_source/devices/nvidia_cmem_latency_pmu_<socket-id>. + +Example usage:: + + perf stat -a -e '{nvidia_cmem_latency_pmu_0/rd_req/,nvidia_cmem_latency_pmu_0/rd_cum_outs/,nvidia_cmem_latency_pmu_0/cycles/}' |