diff options
Diffstat (limited to 'tools/testing/selftests/rcutorture/bin/jitter.sh')
| -rwxr-xr-x | tools/testing/selftests/rcutorture/bin/jitter.sh | 101 |
1 files changed, 66 insertions, 35 deletions
diff --git a/tools/testing/selftests/rcutorture/bin/jitter.sh b/tools/testing/selftests/rcutorture/bin/jitter.sh index 3633828375e3..3c1e5d3f8805 100755 --- a/tools/testing/selftests/rcutorture/bin/jitter.sh +++ b/tools/testing/selftests/rcutorture/bin/jitter.sh @@ -1,69 +1,95 @@ #!/bin/bash +# SPDX-License-Identifier: GPL-2.0+ # # Alternate sleeping and spinning on randomly selected CPUs. The purpose # of this script is to inflict random OS jitter on a concurrently running # test. # -# Usage: jitter.sh me duration [ sleepmax [ spinmax ] ] +# Usage: jitter.sh me jittering-path duration [ sleepmax [ spinmax ] ] # # me: Random-number-generator seed salt. # duration: Time to run in seconds. +# jittering-path: Path to file whose removal will stop this script. # sleepmax: Maximum microseconds to sleep, defaults to one second. # spinmax: Maximum microseconds to spin, defaults to one millisecond. # -# 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, you can access it online at -# http://www.gnu.org/licenses/gpl-2.0.html. -# # Copyright (C) IBM Corporation, 2016 # -# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com> +# Authors: Paul E. McKenney <paulmck@linux.ibm.com> me=$(($1 * 1000)) -duration=$2 -sleepmax=${3-1000000} -spinmax=${4-1000} +jittering=$2 +duration=$3 +sleepmax=${4-1000000} +spinmax=${5-1000} n=1 -starttime=`awk 'BEGIN { print systime(); }' < /dev/null` +starttime=`gawk 'BEGIN { print systime(); }' < /dev/null` + +nohotplugcpus= +for i in /sys/devices/system/cpu/cpu[0-9]* +do + if test -f $i/online + then + : + else + curcpu=`echo $i | sed -e 's/^[^0-9]*//'` + nohotplugcpus="$nohotplugcpus $curcpu" + fi +done + +# Uses global variables startsecs, startns, endsecs, endns, and limit. +# Exit code is success for time not yet elapsed and failure otherwise. +function timecheck { + local done=`awk -v limit=$limit \ + -v startsecs=$startsecs \ + -v startns=$startns \ + -v endsecs=$endsecs \ + -v endns=$endns < /dev/null ' + BEGIN { + delta = (endsecs - startsecs) * 1000 * 1000; + delta += int((endns - startns) / 1000); + print delta >= limit; + }'` + return $done +} while : do # Check for done. - t=`awk -v s=$starttime 'BEGIN { print systime() - s; }' < /dev/null` + t=`gawk -v s=$starttime 'BEGIN { print systime() - s; }' < /dev/null` if test "$t" -gt "$duration" then exit 0; fi - # Set affinity to randomly selected CPU - cpus=`ls /sys/devices/system/cpu/*/online | - sed -e 's,/[^/]*$,,' -e 's/^[^0-9]*//' | - grep -v '^0*$'` + # Check for stop request. + if ! test -f "$jittering" + then + exit 1; + fi + + # Set affinity to randomly selected online CPU + if cpus=`grep 1 /sys/devices/system/cpu/*/online 2>&1 | + sed -e 's,/[^/]*$,,' -e 's/^[^0-9]*//'` + then + : + else + cpus= + fi + # Do not leave out non-hot-pluggable CPUs + cpus="$cpus $nohotplugcpus" + cpumask=`awk -v cpus="$cpus" -v me=$me -v n=$n 'BEGIN { srand(n + me + systime()); ncpus = split(cpus, ca); - curcpu = ca[int(rand() * ncpus + 1)]; - mask = lshift(1, curcpu); - if (mask + 0 <= 0) - mask = 1; - printf("%#x\n", mask); + print ca[int(rand() * ncpus + 1)]; }' < /dev/null` n=$(($n+1)) - if ! taskset -p $cpumask $$ > /dev/null 2>&1 + if ! taskset -c -p $cpumask $$ > /dev/null 2>&1 then - echo taskset failure: '"taskset -p ' $cpumask $$ '"' + echo taskset failure: '"taskset -c -p ' $cpumask $$ '"' exit 1 fi @@ -75,15 +101,20 @@ do n=$(($n+1)) sleep .$sleeptime - # Spin a random duration + # Spin a random duration, but with rather coarse granularity. limit=`awk -v me=$me -v n=$n -v spinmax=$spinmax 'BEGIN { srand(n + me + systime()); printf("%06d", int(rand() * spinmax)); }' < /dev/null` n=$(($n+1)) - for i in {1..$limit} + startsecs=`date +%s` + startns=`date +%N` + endsecs=$startns + endns=$endns + while timecheck do - echo > /dev/null + endsecs=`date +%s` + endns=`date +%N` done done |