vfsstat_example.txt

Demonstrations of vfsstat, the Linux eBPF/bcc version.


This traces some common VFS calls and prints per-second summaries. By default,
the output interval is one second:

# ./vfsstat
TIME         READ/s  WRITE/s CREATE/s   OPEN/s  FSYNC/s
18:35:32:       231       12        4       98        0
18:35:33:       274       13        4      106        0
18:35:34:       586       86        4      251        0
18:35:35:       241       15        4       99        0
18:35:36:       232       10        4       98        0
18:35:37:       244       10        4      107        0
18:35:38:       235       13        4       97        0
18:35:39:      6749     2633        4     1446        0
18:35:40:       277       31        4      115        0
18:35:41:       238       16        6      102        0
18:35:42:       284       50        8      114        0
^C


Here we are using an output interval of five seconds, and printing three output
lines:

# ./vfsstat 5 3
TIME         READ/s  WRITE/s CREATE/s   OPEN/s  FSYNC/s
18:35:55:       238        8        3      101        0
18:36:00:       962      233        4      247        0
18:36:05:       241        8        3      100        0


Full usage:

# ./vfsstat -h
usage: vfsstat [-h] [-p PID] [interval] [count]

Count some VFS calls.

positional arguments:
  interval           output interval, in seconds
  count              number of outputs

optional arguments:
  -h, --help         show this help message and exit
  -p PID, --pid PID  trace this PID only

examples:
    ./vfsstat             # count some VFS calls per second
    ./vfsstat -p 185      # trace PID 185 only
    ./vfsstat 2 5         # print 2 second summaries, 5 times