On Wed, May 29, 2019 at 11:28 AM Ming Lei <tom.leiming@xxxxxxxxx> wrote: > > Hi, > > Looks ebpf trace doesn't work during cpu hotplug, see the following trace: > > 1) trace two functions called during CPU unplug via bcc/trace > > /usr/share/bcc/tools/trace -T 'takedown_cpu "%d", arg1' 'take_cpu_down' > > 2) put cpu7 offline via: > > echo 0 > /sys/devices/system/cpu/cpu7/online > > 3) only trace on 'takedown_cpu' is dumped via bcc/trace: > > TIME PID TID COMM FUNC - > 03:23:17 733 733 bash takedown_cpu 7 > > The lost trace on 'take_cpu_down' can never be shown, even though > CPU7 is switched ON again. > > take_cpu_down is called via stop_machine_cpuslocked. >From a user view, I think the tool should be reliable to collect traces any time. So ping on this issue... Thanks, Ming Lei
