Provided by: perf-tools-unstable_0.0.1~20150130+git85414b0-1_all bug

NAME

       funccount  -  count kernel function calls matching specified wildcards.
       Uses Linux ftrace.

SYNOPSIS

       funccount [-hT] [-i secs] [-d secs] [-t top] funcstring

DESCRIPTION

       This tool is a quick way to determine which kernel functions are  being
       called,   and   at   what  rate.  It  uses  ftrace  function  profiling
       capabilities.

       WARNING: This uses  dynamic  tracing  of  (what  can  be  many)  kernel
       functions,  and  could  cause  kernel panics or freezes. Test, and know
       what you are doing, before use.

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

REQUIREMENTS

       CONFIG_FUNCTION_PROFILER,  which  you  may  already  have  enabled  and
       available on recent kernels, and awk.

OPTIONS

       -d seconds Total duration of the trace.

       -h     Print usage message.

       -i seconds
              Print an interval summary every so many seconds.

       -t top Print top number of entries only.

       -T     Include timestamp on each summary.

       funcstring
              A  function  name  to  trace,  which may include file glob style
              wildcards ("*") at the beginning or ending of a string only. Eg,
              "vfs*" means match "vfs" followed by anything.

EXAMPLES

       Count every kernel function beginning with "bio_", until Ctrl-C is hit:
              # funccount 'bio_*'

       Count  every  "tcp_*"  kernel  function,  and print a summary every one
       second, five in total:
              # funccount -i 1 -d 5 'tcp_*'

       Count every "ext4*" kernel function, and print the top 20  when  Ctrl-C
       is hit:
              # funccount -t 20 'ext4*'

FIELDS

       FUNC   Kernel function name.

       COUNT  Number  of  times  this  function  was called during the tracing
              interval.

OVERHEAD

       This uses the ftrace profiling framework, which does in-kernel  counts,
       lowering the overhead (compared to tracing each event).

SOURCE

       This is from the perf-tools collection:

              https://github.com/brendangregg/perf-tools

       Also  look  under  the  examples  directory  for a text file containing
       example usage, output, and commentary for this tool.

OS

       Linux

STABILITY

       Unstable - in development.

AUTHOR

       Brendan Gregg

SEE ALSO

       functrace(8)