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perf-tools/kernel/funccount
2014-07-31 15:46:18 -07:00

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#!/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"