Manual: funccount-bpfcc

funccount(8)					   System Manager's Manual					funccount(8)

NAME
       funccount - Count function, tracepoint, and USDT probe calls matching a pattern. Uses Linux eBPF/bcc.

SYNOPSIS
       funccount [-h] [-p PID] [-i INTERVAL] [-d DURATION] [-T] [-r] [-c CPU] [-D] pattern

DESCRIPTION
       This tool is a quick way to determine which functions are being called, and at what rate. It uses in-kernel eBPF maps
       to count function calls.

       WARNING:	 This  uses  dynamic tracing of (what can be many) functions, an activity that has had issues on some kernel
       versions (risk of panics or freezes). Test, and know what you are doing, before use.

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

REQUIREMENTS
       CONFIG_BPF and bcc.

OPTIONS
       pattern Search pattern. Supports "*" wildcards. See EXAMPLES. You can also use -r for regular expressions.

       -h     Print usage message.

       -p PID Trace this process ID only.

       -i INTERVAL
	      Print output every interval seconds.

       -d DURATION
	      Total duration of trace in seconds.

       -T     Include timestamps on output.

       -r     Use regular expressions for the search pattern.

       -D     Print the BPF program before starting (for debugging purposes).

       -c CPU Trace on this CPU only.

EXAMPLES
       Count kernel functions beginning with "vfs_", until Ctrl-C is hit:
	      # funccount 'vfs_*'

       Count kernel functions beginning with "tcp_send", until Ctrl-C is hit:
	      # funccount 'tcp_send*'

       Print kernel functions beginning with "vfs_", every second:
	      # funccount -i 1 'vfs_*'

       Print kernel functions beginning with "vfs_", for ten seconds only:
	      # funccount -d 10 'vfs_*'

       Match kernel functions beginning with "vfs_", using regular expressions:
	      # funccount -r '^vfs_.*'

       Count vfs calls for process ID 181 only:
	      # funccount -p 181 'vfs_*'

       Count calls to the sched_fork tracepoint, indicating a fork() performed:
	      # funccount t:sched:sched_fork

       Count all GC USDT probes in the Node process:
	      # funccount -p 185 u:node:gc*

       Count all malloc() calls in libc:
	      # funccount c:malloc

       Count kernel functions beginning with "vfs_" on CPU 1 only:
	      # funccount -c 1 'vfs_*'

FIELDS
       FUNC   Function name

       COUNT  Number of calls while tracing

OVERHEAD
       This traces functions and maintains in-kernel counts, which are asynchronously copied to user-space. While  the	rate
       of calls be very high (>1M/sec), this is a relatively efficient way to trace these events, and so the overhead is ex‐
       pected to be small for normal workloads.	 Measure in a test environment before use.

SOURCE
       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.

OS
       Linux

STABILITY
       Unstable - in development.

AUTHOR
       Brendan Gregg, Sasha Goldshtein

SEE ALSO
       stackcount(8) funclatency(8) vfscount(8)

USER COMMANDS						 2015-08-18						funccount(8)