#!/bin/bash # # 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. # # 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> me=$(($1 * 1000)) duration=$2 sleepmax=${3-1000000} spinmax=${4-1000} n=1 starttime=`awk 'BEGIN { print systime(); }' < /dev/null` while : do # Check for done. t=`awk -v s=$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,/[^/]*$,,' -e 's/^[^0-9]*//' | grep -v '^0*$'` 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
Name | Type | Size | Permission | Actions |
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config2frag.sh | File | 1.01 KB | 0755 |
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configNR_CPUS.sh | File | 1.3 KB | 0755 |
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config_override.sh | File | 1.42 KB | 0755 |
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configcheck.sh | File | 1.55 KB | 0755 |
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configinit.sh | File | 2.4 KB | 0755 |
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cpus2use.sh | File | 1.25 KB | 0755 |
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functions.sh | File | 6.43 KB | 0644 |
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jitter.sh | File | 2.44 KB | 0755 |
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kvm-build.sh | File | 1.9 KB | 0755 |
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kvm-recheck-lock.sh | File | 1.46 KB | 0755 |
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kvm-recheck-rcu.sh | File | 2.14 KB | 0755 |
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kvm-recheck-rcuperf-ftrace.sh | File | 3.25 KB | 0755 |
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kvm-recheck-rcuperf.sh | File | 2.56 KB | 0755 |
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kvm-recheck.sh | File | 2.19 KB | 0755 |
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kvm-test-1-run.sh | File | 8.53 KB | 0755 |
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kvm.sh | File | 12.78 KB | 0755 |
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parse-build.sh | File | 1.55 KB | 0755 |
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parse-console.sh | File | 2.52 KB | 0755 |
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parse-torture.sh | File | 2.57 KB | 0755 |
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