Re: [9front] qemu clock/timer issue

[hiro <23hiro@gmail.com>]

do you have timesync running twice? check in ps output.

On 2/5/22, Michael Forney <mforney@mforney.org> wrote:
> I was recently running 9front in a VM on linux (qemu, with
> -enable-kvm), and noticed several weird timing/clock issues. The date
> command gives wildly varying results +- 1 minute:
>
> cpu% date
> Fri Feb  4 17:39:23 PST 2022
> cpu% date
> Fri Feb  4 17:39:12 PST 2022
> cpu% date
> Fri Feb  4 17:40:19 PST 2022
> cpu% date
> Fri Feb  4 17:39:18 PST 2022
>
> `sleep 1` exits pretty much instantly, stats moves through the entire
> width in a second or two, and clicking in scrollbars starts repeating
> immediately.
>
> I notice the following messages in my dmesg:
> kvm: vcpu 3: requested 38141 ns lapic timer period limited to 200000 ns
> kvm: vcpu 1: requested 9449 ns lapic timer period limited to 200000 ns
> kvm: vcpu 2: requested 51204 ns lapic timer period limited to 200000 ns
> kvm: vcpu 0: requested 74421 ns lapic timer period limited to 200000 ns
>
> I don't remember this problem last time I ran 9front in qemu (around a
> year ago), so I looked through commit history and found one commit
> that seemed like it might be related:
> http://git.9front.org/plan9front/plan9front/a05bab362f66ddd6fa65f2e7cda9eaaa0217ec08/commit.html
>
> To check, I tried setting *nohpet=1 in my plan9.ini, which *seems* to
> have solved the problem, though I still see those same messages in
> dmesg on the linux host (but now the requested lapic timer period is
> always around 100000 ns or greater).
>
> Anyone know what's going on here?
>