xref: /aosp_15_r20/external/bcc/examples/tracing/biolatpcts_example.txt (revision 387f9dfdfa2baef462e92476d413c7bc2470293e)
1Demonstrations of biolatpcts.py, the Linux eBPF/bcc version.
2
3
4This traces block I/O and uses layered percpu arrays to bucket the completion
5latencies. Latency percentiles are calculated periodically from the buckets.
6
7# ./biolatpcts.py
8p50=595.0us p75=685.0us p90=1500.0us p99=2500.0us
9p50=55.0us p75=95.0us p90=305.0us p99=2500.0us
10p50=385.0us p75=655.0us p90=1500.0us p99=2500.0us
11[...]
12
13The latency is measured from I/O request to the device, to the device
14completion. This excludes latency spent queued in the OS.
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16This is a simplified example to demonstrate the calculation of latency
17percentiles. See tools/biolatpcts.py for the full utility.
18