vfsstat_example.txt

Demonstrations of vfsstat, the Linux bpftrace/eBPF version.


This traces some common VFS calls (see the script for the list) and prints
per-second summaries.

# vfsstat.bt
Attaching 8 probes...
Tracing key VFS calls... Hit Ctrl-C to end.
21:30:38
@[vfs_write]: 1274
@[vfs_open]: 8675
@[vfs_read]: 11515

21:30:39
@[vfs_write]: 1155
@[vfs_open]: 8077
@[vfs_read]: 10398

21:30:40
@[vfs_write]: 1222
@[vfs_open]: 8554
@[vfs_read]: 11011

21:30:41
@[vfs_write]: 1230
@[vfs_open]: 8605
@[vfs_read]: 11077

21:30:42
@[vfs_write]: 1229
@[vfs_open]: 8591
@[vfs_read]: 11061

^C

Each second, a timestamp is printed ("HH:MM:SS") followed by common VFS
functions and the number of calls for that second. While tracing, the vfs_read()
kernel function was most frequent, occurring over 10,000 times per second.


There is another version of this tool in bcc: https://github.com/iovisor/bcc
The bcc version provides command line options.