Commit 6e524a60 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcutorture: Add OS-jitter capability 



This commit adds a --jitter OS-jitter capability to expose bugs based
on no-delay assumptions.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 480b1eb6

tools/testing/selftests/rcutorture/bin/jitter.sh

0 → 100755
+90 −0
Original line number Diff line number Diff line 
#!/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

tools/testing/selftests/rcutorture/bin/kvm.sh

+18 −0
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ resdir="" 
configs=""

cpus=0

ds=`date +%Y.%m.%d-%H:%M:%S`

jitter=0



. functions.sh
@@ -63,6 +64,7 @@ usage () { 
	echo "       --dryrun sched|script"

	echo "       --duration minutes"

	echo "       --interactive"

	echo "       --jitter N [ maxsleep (us) [ maxspin (us) ] ]"

	echo "       --kmake-arg kernel-make-arguments"

	echo "       --mac nn:nn:nn:nn:nn:nn"

	echo "       --no-initrd"
@@ -122,6 +124,11 @@ do 
	--interactive)

		TORTURE_QEMU_INTERACTIVE=1; export TORTURE_QEMU_INTERACTIVE

		;;

	--jitter)

		checkarg --jitter "(# threads [ sleep [ spin ] ])" $# "$2" '^-\{,1\}[0-9]\+\( \+[0-9]\+\)\{,2\} *$' '^error$'

		jitter="$2"

		shift

		;;

	--kmake-arg)

		checkarg --kmake-arg "(kernel make arguments)" $# "$2" '.*' '^error$'

		TORTURE_KMAKE_ARG="$2"
@@ -299,6 +306,7 @@ awk < $T/cfgcpu.pack \ 
	-v CONFIGDIR="$CONFIGFRAG/" \

	-v KVM="$KVM" \

	-v ncpus=$cpus \

	-v jitter="$jitter" \

	-v rd=$resdir/$ds/ \

	-v dur=$dur \

	-v TORTURE_QEMU_ARG="$TORTURE_QEMU_ARG" \
@@ -359,6 +367,16 @@ function dump(first, pastlast, batchnum) 
		print "\techo ----", cfr[j], cpusr[j] ovf ": Starting kernel. `date` >> " rd "/log";

		print "fi"

	}

	njitter = 0;

	split(jitter, ja);

	if (ja[1] == -1 && ncpus == 0)

		njitter = 1;

	else if (ja[1] == -1)

		njitter = ncpus;

	else

		njitter = ja[1];

	for (j = 0; j < njitter; j++)

		print "jitter.sh " j " " dur " " ja[2] " " ja[3] "&"

	print "wait"

	print "if test -z \"$TORTURE_BUILDONLY\""

	print "then"