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)