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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-06-10 00:09:21 +0300
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-07-25 02:04:16 +0300
commitc234ee4b82682a64dbe8027a0a4dab36569133f2 (patch)
tree45308534d1f07938a534d68cb3dc68cb5638b03a /tools/testing/selftests/rcutorture
parentb3c983142d4584c9d506b1ed31b65f4292b4aea8 (diff)
downloadlinux-c234ee4b82682a64dbe8027a0a4dab36569133f2.tar.xz
rcutorture: Use nr_cpus rather than maxcpus to limit test size
The maxcpus= kernel boot parameter limits the number of CPUs brought online at boot time, but it does nothing to prevent additional CPUs from being brought up later. Placing a hard cap on the total number of CPUs is instead the job of the nr_cpus= boot parameter. This commit therefore switches the configfrag_boot_cpus() shell function from maxcpus= to nr_cpus=. This commit also adds a nr_cpus=43 kernel parameter to RCU's TREE01 test scenario, but retains the maxcpus=8 kernel parameter in order to test the ability of RCU expedited grace periods to handle new CPUs coming online for the first time during grace-period initialization. Finally, this commit makes the torture scheduling allow maxcpus= to override other means of specifying the number of CPUs to allow for. This last works because the torture kernel modules size their workloads based on the number of CPUs present at the start of the test, not the ultimate number of CPUs. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'tools/testing/selftests/rcutorture')
-rw-r--r--tools/testing/selftests/rcutorture/bin/functions.sh27
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm.sh1
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE01.boot2
3 files changed, 28 insertions, 2 deletions
diff --git a/tools/testing/selftests/rcutorture/bin/functions.sh b/tools/testing/selftests/rcutorture/bin/functions.sh
index 1426a9b97494..07a13779eece 100644
--- a/tools/testing/selftests/rcutorture/bin/functions.sh
+++ b/tools/testing/selftests/rcutorture/bin/functions.sh
@@ -66,9 +66,34 @@ configfrag_boot_params () {
# configfrag_boot_cpus bootparam-string config-fragment-file config-cpus
#
-# Decreases number of CPUs based on any maxcpus= boot parameters specified.
+# Decreases number of CPUs based on any nr_cpus= boot parameters specified.
configfrag_boot_cpus () {
local bootargs="`configfrag_boot_params "$1" "$2"`"
+ local nr_cpus
+ if echo "${bootargs}" | grep -q 'nr_cpus=[0-9]'
+ then
+ nr_cpus="`echo "${bootargs}" | sed -e 's/^.*nr_cpus=\([0-9]*\).*$/\1/'`"
+ if test "$3" -gt "$nr_cpus"
+ then
+ echo $nr_cpus
+ else
+ echo $3
+ fi
+ else
+ echo $3
+ fi
+}
+
+# configfrag_boot_maxcpus bootparam-string config-fragment-file config-cpus
+#
+# Decreases number of CPUs based on any maxcpus= boot parameters specified.
+# This allows tests where additional CPUs come online later during the
+# test run. However, the torture parameters will be set based on the
+# number of CPUs initially present, so the scripting should schedule
+# test runs based on the maxcpus= boot parameter controlling the initial
+# number of CPUs instead of on the ultimate number of CPUs.
+configfrag_boot_maxcpus () {
+ local bootargs="`configfrag_boot_params "$1" "$2"`"
local maxcpus
if echo "${bootargs}" | grep -q 'maxcpus=[0-9]'
then
diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh
index cdb32aa79366..b55895fb10ed 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm.sh
@@ -212,6 +212,7 @@ do
then
cpu_count=`configNR_CPUS.sh $CONFIGFRAG/$CF1`
cpu_count=`configfrag_boot_cpus "$TORTURE_BOOTARGS" "$CONFIGFRAG/$CF1" "$cpu_count"`
+ cpu_count=`configfrag_boot_maxcpus "$TORTURE_BOOTARGS" "$CONFIGFRAG/$CF1" "$cpu_count"`
for ((cur_rep=0;cur_rep<$config_reps;cur_rep++))
do
echo $CF1 $cpu_count >> $T/cfgcpu
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE01.boot b/tools/testing/selftests/rcutorture/configs/rcu/TREE01.boot
index 1d14e1383016..9f3a4d28e508 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE01.boot
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE01.boot
@@ -1,4 +1,4 @@
-rcutorture.torture_type=rcu_bh maxcpus=8
+rcutorture.torture_type=rcu_bh maxcpus=8 nr_cpus=43
rcutree.gp_preinit_delay=3
rcutree.gp_init_delay=3
rcutree.gp_cleanup_delay=3