Re: KVM on POWER8 host lock up since 10d91611f426 ("powerpc/64s: Reimplement book3s idle code in C")

Am 31.08.20 um 03:14 schrieb Nicholas Piggin:

So hwthread_state is never getting back to to HWTHREAD_IN_IDLE on
those threads. I wonder what they are doing. POWER8 doesn't have a good
NMI IPI and I don't know if it supports pdbg dumping registers from the
BMC unfortunately.

Do the messages always come in pairs of CPUs?

well,
- one problem is that at some point the machine just locks up completely,
  so I can not tell if there were lines not printed any more and in some
  cases all I get is a single line
- looking at the stats in generally it's either one cpu printed several
  times or a pair ("not strictly") alternatingly

2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.029821] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.058630] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.108268] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.210206] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.323465] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.334420] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.345470] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.395185] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.517182] KVM: couldn't grab cpu 92
2020-07-30T03:16:17+00:00 obs-power8-03 kernel: [51284.600716] KVM: couldn't grab cpu 92
2020-07-30T03:16:18+00:00 obs-power8-03 kernel: [51286.201589] KVM: couldn't grab cpu 92
2020-07-30T03:16:19+00:00 obs-power8-03 kernel: [51286.627273] KVM: couldn't grab cpu 92

2020-07-30T16:44:16+00:00 obs-power8-04 kernel: [30099.726288] KVM: couldn't grab cpu 61
2020-07-30T16:44:16+00:00 obs-power8-04 kernel: [30099.736843] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30099.747429] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30099.877138] KVM: couldn't grab cpu 61
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30099.916422] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30099.931755] KVM: couldn't grab cpu 61
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.029003] KVM: couldn't grab cpu 61
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.334895] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.392713] KVM: couldn't grab cpu 61
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.569011] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.617048] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.628107] KVM: couldn't grab cpu 125
2020-07-30T16:44:18+00:00 obs-power8-04 kernel: [30100.809046] KVM: couldn't grab cpu 125
2020-07-30T16:44:18+00:00 obs-power8-04 kernel: [30101.001097] KVM: couldn't grab cpu 61
2020-07-30T16:44:19+00:00 obs-power8-04 kernel: [30102.109007] KVM: couldn't grab cpu 125
2020-07-30T16:44:19+00:00 obs-power8-04 kernel: [30102.254470] KVM: couldn't grab cpu 61

I'm not sure where to start with reproducing, I'll have to try. How many
vCPUs in the guests? Do you have several guests running at once?

Thanks,
Nick

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