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authorPaul E. McKenney <paulmck@kernel.org>2019-11-25 23:33:28 +0100
committerPaul E. McKenney <paulmck@kernel.org>2019-12-09 22:00:30 +0100
commitb22eb7cefb9d31cf862542f9cef90f97c0294842 (patch)
treeed9b4e7fa0edab8807029f98ed04bb6f080d5bd9 /tools/testing/selftests/rcutorture
parenttorture: Allow "CFLIST" to specify default list of scenarios (diff)
downloadlinux-b22eb7cefb9d31cf862542f9cef90f97c0294842.tar.xz
linux-b22eb7cefb9d31cf862542f9cef90f97c0294842.zip
torture: Hoist calls to lscpu to higher-level kvm.sh script
On some kernels, concurrent calls to the lscpu command result in severe slowdowns. For example, on v4.16, a single lscpu invocation takes about two milliseconds, four concurrent invocations more than two seconds, and 16 concurrent invocations more than 20 seconds. Given that the only goal is to learn the number of CPUs, invoking lscpu but once suffices. This commit therefore invokes lscpu early in kvm.sh execution, setting the initial value of the TORTURE_ALLOTED_CPUS environment variable. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'tools/testing/selftests/rcutorture')
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh7
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm.sh11
2 files changed, 11 insertions, 7 deletions
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
index 1d98992d1c34..e0352304b98b 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
@@ -133,11 +133,10 @@ fi
qemu_args="-enable-kvm -nographic $qemu_args"
cpu_count=`configNR_CPUS.sh $resdir/ConfigFragment`
cpu_count=`configfrag_boot_cpus "$boot_args" "$config_template" "$cpu_count"`
-vcpus=`identify_qemu_vcpus`
-if test $cpu_count -gt $vcpus
+if test "$cpu_count" -gt "$TORTURE_ALLOTED_CPUS"
then
- echo CPU count limited from $cpu_count to $vcpus | tee -a $resdir/Warnings
- cpu_count=$vcpus
+ echo CPU count limited from $cpu_count to $TORTURE_ALLOTED_CPUS | tee -a $resdir/Warnings
+ cpu_count=$TORTURE_ALLOTED_CPUS
fi
qemu_args="`specify_qemu_cpus "$QEMU" "$qemu_args" "$cpu_count"`"
diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh
index e19151c6e5e5..78d18ab8e954 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm.sh
@@ -24,7 +24,9 @@ dur=$((30*60))
dryrun=""
KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
PATH=${KVM}/bin:$PATH; export PATH
-TORTURE_ALLOTED_CPUS=""
+. functions.sh
+
+TORTURE_ALLOTED_CPUS="`identify_qemu_vcpus`"
TORTURE_DEFCONFIG=defconfig
TORTURE_BOOT_IMAGE=""
TORTURE_INITRD="$KVM/initrd"; export TORTURE_INITRD
@@ -40,8 +42,6 @@ cpus=0
ds=`date +%Y.%m.%d-%H:%M:%S`
jitter="-1"
-. functions.sh
-
usage () {
echo "Usage: $scriptname optional arguments:"
echo " --bootargs kernel-boot-arguments"
@@ -93,6 +93,11 @@ do
checkarg --cpus "(number)" "$#" "$2" '^[0-9]*$' '^--'
cpus=$2
TORTURE_ALLOTED_CPUS="$2"
+ max_cpus="`identify_qemu_vcpus`"
+ if test "$TORTURE_ALLOTED_CPUS" -gt "$max_cpus"
+ then
+ TORTURE_ALLOTED_CPUS=$max_cpus
+ fi
shift
;;
--datestamp)