Messages in this thread | | | From | Ming Lei <> | Date | Wed, 29 May 2019 11:28:34 +0800 | Subject | ebpf trace doesn't work during cpu hotplug |
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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.
Thanks, Ming Lei
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