Commit b22eb7ce authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

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: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 25b4da74

tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh

+3 −4
Original line number Diff line number Diff line
@@ -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"`"

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

+8 −3
Original line number Diff line number Diff line
@@ -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)

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