vfsstat - Statistics for some common VFS calls. Uses Linux eBPF/bcc.

       Brendan Gregg

       This  traces  some  common  VFS  calls  and  prints  per-second summaries. This can be useful for general
       workload characterization, and looking for patterns in operation usage over time.

       This works by tracing some kernel vfs functions using dynamic tracing, and will need  updating  to  match
       any  changes  to  these  functions.  Edit  the  script  to customize which functions are traced. Also see
       vfscount, which is more easily customized to trace multiple functions.

       Since this uses BPF, only the root user can use this tool.

       Print summaries each second:
              # vfsstat

       Print output every five seconds, three times:
              # vfsstat53

       READ/s Number of vfs_read() calls as a per-second average.

       WRITE/s
              Number of vfs_write() calls as a per-second average.

       CREATE/s
              Number of vfs_create() calls as a per-second average.

       OPEN/s Number of vfs_open() calls as a per-second average.

       FSYNC/s
              Number of vfs_fsync() calls as a per-second average.

       vfsstat - Statistics for some common VFS calls. Uses Linux eBPF/bcc.

       Linux

       This traces various kernel vfs functions and maintains in-kernel counts, which are asynchronously  copied
       to  user-space.  While  the  rate  of  VFS  operations  can  be very high (>1M/sec), this is a relatively
       efficient way to trace these events, and so the overhead is expected to be small  for  normal  workloads.
       Measure in a test environment.

       CONFIG_BPF and bcc.

vfscount(8)

USER COMMANDS                                      2015-08-18                                         vfsstat(8)

       This is from bcc.

              https://github.com/iovisor/bcc

       Also  look  in  the bcc distribution for a companion _examples.txt file containing example usage, output,
       and commentary for this tool.

       Unstable - in development.

vfsstat [interval [count]]