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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-03-29 14:22:26 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-04-21 13:45:35 -0700
commit6e524a603f0b72281019e4ec29b1022388f9f231 (patch)
treed2d383b3fcc1234153288d080a4e2281bd47bdb1 /tools/testing/selftests/rcutorture/bin/jitter.sh
parent480b1eb659f65be8ed039f1a9db3f762c41c9770 (diff)
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rcutorture: Add OS-jitter capability
This commit adds a --jitter OS-jitter capability to expose bugs based on no-delay assumptions. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'tools/testing/selftests/rcutorture/bin/jitter.sh')
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/jitter.sh90
1 files changed, 90 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 000000000000..3633828375e3
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/bin/jitter.sh
@@ -0,0 +1,90 @@
+#!/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