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Re: timekeeping regression?



At Tue, 18 Jun 2024 21:11:50 -0400, Brad Spencer <brad%anduin.eldar.org@localhost> wrote:
Subject: Re: timekeeping regression?
>
> The drifts and instability I have seen with respect to time have always
> been in the DOMUs, especially pure PV DOMUs with more than one vcpu.

Do you have your dom0 vcpus pinned?  I only saw dom0 drift when I
un-pinned their vcpus, otherwise it's rock-solid.

> I suppose the 7.5 days of uptime could not be due to a cron job that
> happens to run at about that time??

No, nothing like that.

I'm thinking wild thoughts right now about how there might be some
adjustment to the vCPU scheduling in the hypervisor after that much time
elapses, and that somehow upsets the RDTSC emulation.  Or maybe there's
just a plain old bug in Xen's RDTSC emulation.  Either seem highly
unlikely though.

After all it does have to have something to do with the Xen hypervisor
as I didn't see time warps in domUs either until I upgraded to 4.18.

--
					Greg A. Woods <gwoods%acm.org@localhost>

Kelowna, BC     +1 250 762-7675           RoboHack <woods%robohack.ca@localhost>
Planix, Inc. <woods%planix.com@localhost>     Avoncote Farms <woods%avoncote.ca@localhost>

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