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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>
This commit is contained in:
Paul E. McKenney 2019-11-25 14:33:28 -08:00
parent 25b4da74a9
commit b22eb7cefb
2 changed files with 11 additions and 7 deletions
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7
tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
View File

@ -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"`"

11
tools/testing/selftests/rcutorture/bin/kvm.sh
View File

@ -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)