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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/testing/selftests/rcutorture/bin/jitter.sh | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/testing/selftests/rcutorture/bin/jitter.sh')
-rwxr-xr-x | tools/testing/selftests/rcutorture/bin/jitter.sh | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/tools/testing/selftests/rcutorture/bin/jitter.sh b/tools/testing/selftests/rcutorture/bin/jitter.sh new file mode 100755 index 000000000..188b864bc --- /dev/null +++ b/tools/testing/selftests/rcutorture/bin/jitter.sh @@ -0,0 +1,102 @@ +#!/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 ] ] +# +# me: Random-number-generator seed salt. +# duration: Time to run in seconds. +# sleepmax: Maximum microseconds to sleep, defaults to one second. +# spinmax: Maximum microseconds to spin, defaults to one millisecond. +# +# Copyright (C) IBM Corporation, 2016 +# +# Authors: Paul E. McKenney <paulmck@linux.ibm.com> + +me=$(($1 * 1000)) +duration=$2 +sleepmax=${3-1000000} +spinmax=${4-1000} + +n=1 + +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 $curcpu" + fi +done + +while : +do + # Check for done. + t=`gawk -v s=$starttime 'BEGIN { print systime() - s; }' < /dev/null` + if test "$t" -gt "$duration" + then + exit 0; + fi + + # Check for stop request. + if test -f "$TORTURE_STOPFILE" + then + exit 1; + fi + + # Set affinity to randomly selected online CPU + if cpus=`grep 1 /sys/devices/system/cpu/*/online 2>&1 | + sed -e 's,/[^/]*$,,' -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); + }' < /dev/null` + n=$(($n+1)) + if ! taskset -p $cpumask $$ > /dev/null 2>&1 + then + echo taskset failure: '"taskset -p ' $cpumask $$ '"' + exit 1 + fi + + # Sleep a random duration + sleeptime=`awk -v me=$me -v n=$n -v sleepmax=$sleepmax 'BEGIN { + srand(n + me + systime()); + printf("%06d", int(rand() * sleepmax)); + }' < /dev/null` + n=$(($n+1)) + sleep .$sleeptime + + # Spin a random duration + 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} + do + echo > /dev/null + done +done + +exit 1 |