#!/bin/bash # # funccount - count kernel function calls matching specified wildcards. # Uses Linux ftrace. # # This is a proof of concept using Linux ftrace capabilities on older kernels, # and works by using function profiling: in-kernel counters. # # USAGE: funccount [-hT] [-i secs] [-d secs] [-t top] funcstring # eg, # funccount 'ext3*' # count all ext3* kernel function calls # # Run "funccount -h" for full usage. # # WARNING: This uses dynamic tracing of kernel functions, and could cause # kernel panics or freezes. Test, and know what you are doing, before use. # # REQUIREMENTS: CONFIG_FUNCTION_PROFILER, awk. # # From perf-tools: https://github.com/brendangregg/perf-tools # # COPYRIGHT: Copyright (c) 2014 Brendan Gregg. # # This program is free software; you can redistribute it and/or # modify it under the terms of the GNU General Public License # as published by the Free Software Foundation; either version 2 # of the License, or (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software Foundation, # Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. # # (http://www.gnu.org/copyleft/gpl.html) # # 12-Jul-2014 Brendan Gregg Created this. ### default variables tracing=/sys/kernel/debug/tracing opt_duration=0; duration=; opt_interval=0; interval=999999; opt_timestamp=0 opt_tail=0; tcmd=cat; ttext= trap 'quit=1' INT QUIT TERM PIPE HUP # sends execution to end tracing section function usage { cat <<-END >&2 USAGE: funccount [-hT] [-i secs] [-d secs] [-t top] funcstring -d seconds # total duration of trace -h # this usage message -i seconds # interval summary -t top # show top num entries only -T # include timestamp (for -i) eg, funccount 'vfs*' # trace all funcs that match "vfs*" funccount -d 5 'tcp*' # trace "tcp*" funcs for 5 seconds funccount -t 10 'ext3*' # show top 10 "ext3*" funcs funccount -i 1 'ext3*' # summary every 1 second funccount -i 1 -d 5 'ext3*' # 5 x 1 second summaries See the man page and example file for more info. END exit } function warn { if ! eval "$@"; then echo >&2 "WARNING: command failed \"$@\"" fi } function die { echo >&2 "$@" exit 1 } ### process options while getopts d:hi:t:T opt do case $opt in d) opt_duration=1; duration=$OPTARG ;; i) opt_interval=1; interval=$OPTARG ;; t) opt_tail=1; tnum=$OPTARG ;; T) opt_timestamp=1 ;; h|?) usage ;; esac done shift $(( $OPTIND - 1 )) ### option logic (( $# == 0 )) && usage funcs="$1" if (( opt_tail )); then tcmd="tail -$tnum" ttext=" Top $tnum only." fi if (( opt_duration )); then echo "Tracing \"$funcs\" for $duration seconds.$ttext.." else echo "Tracing \"$funcs\".$ttext.. Ctrl-C to end." fi (( opt_duration && !opt_interval )) && interval=$duration ### check permissions cd $tracing || die "ERROR: accessing tracing. Root user? Kernel has FTRACE? debugfs mounted? (mount -t debugfs debugfs /sys/kernel/debug)" ### enable tracing sysctl -q kernel.ftrace_enabled=1 # doesn't set exit status echo "$funcs" > set_ftrace_filter || die "ERROR: enabling \"$funcs\". Exiting." warn "echo nop > current_tracer" if ! echo 1 > function_profile_enabled; then echo > set_ftrace_filter die "ERROR: enabling function profiling."\ "Have CONFIG_FUNCTION_PROFILER? Exiting." fi ### summarize quit=0; secs=0 while (( !quit && (!opt_duration || secs < duration) )); do (( secs += interval )) echo 0 > function_profile_enabled echo 1 > function_profile_enabled sleep $interval echo (( opt_timestamp )) && date printf "%-30s %8s\n" "FUNC" "COUNT" cat trace_stat/function* | awk ' # skip headers by matching on the numeric hit column $2 ~ /[0-9]/ { a[$1] += $2 } END { for (k in a) { printf "%-30s %8d\n", k, a[k] } }' | sort -n -k2 | $tcmd done ### end tracing echo 2>/dev/null echo "Ending tracing..." 2>/dev/null warn "echo 0 > function_profile_enabled" warn "echo > set_ftrace_filter"