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 >