On Thu, Sep 01, 2016 at 02:38:59PM +0200, Jesper Dangaard Brouer wrote: > On Thu, 1 Sep 2016 14:29:25 +0200 > Jesper Dangaard Brouer <bro...@redhat.com> wrote: > > > On Thu, 1 Sep 2016 13:53:56 +0200 > > Peter Zijlstra <pet...@infradead.org> wrote: > > > > > On Thu, Sep 01, 2016 at 01:02:31PM +0200, Jesper Dangaard Brouer wrote: > > > > PID S %CPU TIME+ COMMAND > > > > 3 R 50.0 29:02.23 ksoftirqd/0 > > > > 10881 R 10.7 1:01.61 udp_sink > > > > 10837 R 10.0 1:05.20 udp_sink > > > > 10852 S 10.0 1:01.78 udp_sink > > > > 10862 R 10.0 1:05.19 udp_sink > > > > 10844 S 9.7 1:01.91 udp_sink > > > > > > > > This is strange, why is ksoftirqd/0 getting 50% of the CPU time??? > > > > > > Do you run your udp_sink thingy in a cpu-cgroup? > > > > That was also Paolo's feedback (IRC). I'm not aware of it, but it > > might be some distribution (Fedora 22) default thing. > > Correction, on the server-under-test, I'm actually running RHEL7.2 > > > > How do I verify/check if I have enabled a cpu-cgroup? > > Hannes says I can look in "/proc/self/cgroup" > > $ cat /proc/self/cgroup > 7:net_cls:/ > 6:blkio:/ > 5:devices:/ > 4:perf_event:/ > 3:cpu,cpuacct:/ > 2:cpuset:/ > 1:name=systemd:/user.slice/user-1000.slice/session-c1.scope > > And that "/" indicate I've not enabled cgroups, right?
Mostly so. I think RHEL/Fedora has SCHED_AUTOGROUP enabled, and you can find that through: cat /proc/self/autogroup And disable with the noautogroup boot param, or: echo 0 > /proc/sys/kernel/sched_autogroup_enabled although this latter will leave the current state intact while avoiding creation of any further autogroups iirc.
