On Tue, 18 Jun 2019 18:40:13 +0700 Naruto Nguyen <narutonguyen2018@xxxxxxxxx> wrote: > Hello everyone, > > I have a kvm hypervisor and setup some VMs running OpenSUSE kernel > 4.0. After some reboot, I saw that sometime there is a VM that a > certain core has higher %usr and %sys than other cores. The system is > in ide state. I have some applications running on this VM, but there > is no issue in other VMs. How much higher? And is it always an issue with the same core on the same VM? > > If I enable ftrace in kernel or load any debug jprobe, the load is I'm assuming by "ftrace" you mean the full function tracer? # echo function > /sys/kernel/tracing/current_tracer > back to normal. The pidstat command output does not show the high load > on one core like the "top" command. Could you please let me know if it > is the problem of "top' report higher usage? Any commands that can > help to troubleshoot this issue? I tried "perf" but most of the time > the perf output does not show any function that cause the increase as > well? Not sure, if the malfunction of top or anything else can add > more work load? I would suggest just tracing sched switches and interrupts. That shouldn't affect the load, as it is very low weight. # cd /sys/kernel/tracing # echo 1 > events/sched/sched_waking/enable # echo 1 > events/sched/sched_switch/enable # echo 1 > events/irq/enable And then monitor that. -- Steve
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