NAME

       vfsstat.bt - Count key VFS calls. Uses bpftrace/eBPF.

SYNOPSIS

       vfsstat.bt

DESCRIPTION

       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.

REQUIREMENTS

       CONFIG_BPF and bpftrace.

EXAMPLES

       Count some VFS calls, printing per-second summaries until Ctrl-C is hit:
              # vfsstat.bt

FIELDS

       HH:MM:SS
              Each output summary is prefixed by the time of printing in "HH:MM:SS" format.

       1st    Kernel function name (in @[])

       2nd    Number of calls while tracing

OVERHEAD

       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.

SOURCE

       This is from bpftrace.

              https://github.com/iovisor/bpftrace

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

       This is a bpftrace version of the bcc tool of the same name. The bcc tool may provide more
       options and customizations.

              https://github.com/iovisor/bcc

OS

       Linux

STABILITY

       Unstable - in development.

AUTHOR

       Brendan Gregg

SEE ALSO

       vfscount.bt(8)