name : disksnoop_example.txt Demonstrations of disksnoop.py, the Linux eBPF/bcc version. This traces block I/O, a prints a line to summarize each I/O completed: # ./disksnoop.py TIME(s) T BYTES LAT(ms) 16458043.435457 W 4096 2.73 16458043.435981 W 4096 3.24 16458043.436012 W 4096 3.13 16458043.437326 W 4096 4.44 16458044.126545 R 4096 42.82 16458044.129872 R 4096 3.24 16458044.130705 R 4096 0.73 16458044.142813 R 4096 12.01 16458044.147302 R 4096 4.33 16458044.148117 R 4096 0.71 16458044.148950 R 4096 0.70 16458044.164332 R 4096 15.29 16458044.168003 R 4096 3.58 16458044.171676 R 4096 3.59 16458044.172453 R 4096 0.72 16458044.173213 R 4096 0.71 16458044.173989 R 4096 0.72 16458044.174739 R 4096 0.70 16458044.190334 R 4096 15.52 16458044.196608 R 4096 6.17 16458044.203091 R 4096 6.35 The output includes a basic timestamp (in seconds), the type of I/O (W == write, R == read, M == metadata), the size of the I/O in bytes, and the latency (or duration) of the I/O in milliseconds. The latency is measured from I/O request to the device, to the device completion. This excludes latency spent queued in the OS. Most of the I/O in this example were 0.7 and 4 milliseconds in duration. There was an outlier of 42.82 milliseconds, a read which followed many writes (the high latency may have been caused by the writes still being serviced on the storage device).