| Demonstrations of biolatpcts.py, the Linux eBPF/bcc version. |
| |
| |
| This traces block I/O and uses layered percpu arrays to bucket the completion |
| latencies. Latency percentiles are calculated periodically from the buckets. |
| |
| # ./biolatpcts.py |
| p50=595.0us p75=685.0us p90=1500.0us p99=2500.0us |
| p50=55.0us p75=95.0us p90=305.0us p99=2500.0us |
| p50=385.0us p75=655.0us p90=1500.0us p99=2500.0us |
| [...] |
| |
| The latency is measured from I/O request to the device, to the device |
| completion. This excludes latency spent queued in the OS. |
| |
| This is a simplified example to demonstrate the calculation of latency |
| percentiles. See tools/biolatpcts.py for the full utility. |
