On Wed, Aug 5, 2020 at 2:54 AM Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote: > > > > On 8/4/20 5:30 AM, Colin King wrote: > > From: Colin Ian King <colin.king@xxxxxxxxxxxxx> > > > > The current test will exit with a failure if it cannot set affinity on > > specific CPUs which is problematic when running this on single CPU > > systems. Add a check for the number of CPUs and skip the test if > > the CPU requirement is not met. > > > > Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx> > > --- > > tools/testing/selftests/net/msg_zerocopy.sh | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/tools/testing/selftests/net/msg_zerocopy.sh b/tools/testing/selftests/net/msg_zerocopy.sh > > index 825ffec85cea..97bc527e1297 100755 > > --- a/tools/testing/selftests/net/msg_zerocopy.sh > > +++ b/tools/testing/selftests/net/msg_zerocopy.sh > > @@ -21,6 +21,11 @@ readonly DADDR6='fd::2' > > > > readonly path_sysctl_mem="net.core.optmem_max" > > > > +if [[ $(nproc) -lt 4 ]]; then > > + echo "SKIP: test requires at least 4 CPUs" > > + exit 4 > > +fi > > + > > # No arguments: automated test > > if [[ "$#" -eq "0" ]]; then > > $0 4 tcp -t 1 > > > > Test explicitly uses CPU 2 and 3, right ? > > nproc could be 500, yet cpu 2 or 3 could be offline > > # cat /sys/devices/system/cpu/cpu3/online > 0 > # echo $(nproc) > 71 The cpu affinity is only set to bring some stability across runs. The test does not actually verify that a run with zerocopy is some factor faster than without, as that factor is hard to choose across all platforms. As a result the automated run mainly gives code coverage. It's preferable to always run. And on sched_setaffinity failure log a message about possible jitter and continue. I can send that patch, if the approach sounds good.
