On Fri, Mar 22, 2019 at 11:46:19PM -0400, Joel Fernandes (Google) wrote:
> The rcutorture jitter.sh script selects a random CPU but does not check
> if it is offline or online. This leads to taskset errors many times. On
> my machine, hyper threading is disabled so half the cores are offline
> causing taskset errors a lot of times. Let us fix this by checking from
> only the online CPUs on the system.
>
> Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Good catch!
Please see below for one suggestion for simplification.
Thanx, Paul
> ---
> tools/testing/selftests/rcutorture/bin/jitter.sh | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/rcutorture/bin/jitter.sh b/tools/testing/selftests/rcutorture/bin/jitter.sh
> index 3633828375e3..53bf9d99b5cd 100755
> --- a/tools/testing/selftests/rcutorture/bin/jitter.sh
> +++ b/tools/testing/selftests/rcutorture/bin/jitter.sh
> @@ -47,10 +47,19 @@ do
> exit 0;
> fi
>
> - # Set affinity to randomly selected CPU
> + # Set affinity to randomly selected online CPU
> cpus=`ls /sys/devices/system/cpu/*/online |
cpus=`grep 1 /sys/devices/system/cpu/*/online |
> sed -e 's,/[^/]*$,,' -e 's/^[^0-9]*//' |
> grep -v '^0*$'`
Of course, now I have no idea why I excluded CPU 0... :-/
> +
> + for c in $cpus; do
> + if [ "$(cat /sys/devices/system/cpu/cpu$c/online)" == "1" ];
> + then
> + cpus_tmp="$cpus_tmp $c"
> + fi
> + done
> + cpus=$cpus_tmp
> +
> cpumask=`awk -v cpus="$cpus" -v me=$me -v n=$n 'BEGIN {
> srand(n + me + systime());
> ncpus = split(cpus, ca);
> --
> 2.21.0.392.gf8f6787159e-goog
>
