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Re: [Qemu-devel] [Bug 599958] Re: Timedrift problems with Win7: hpet mis
From: |
Gleb Natapov |
Subject: |
Re: [Qemu-devel] [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups |
Date: |
Tue, 1 Oct 2013 19:33:17 +0300 |
On Tue, Oct 01, 2013 at 11:23:07AM -0500, Ben "Root" Anderson wrote:
> Fair enough in itself, but if HPET is known to have problems with
> arguably the most popular OS family to use as a guest, why is it
> enabled by default?
>
Arguably :) But QEMU defaults are arguably far from been optimal for any
guest.
> On Tue, Oct 1, 2013 at 10:56 AM, Gleb Natapov <address@hidden> wrote:
> > On Tue, Oct 01, 2013 at 09:34:06AM -0000, Ben A wrote:
> >> Apparently this bug's still alive and kicking.
> >>
> > And no plans to fix it. Do not use hpet with windows guests this buys
> > you nothing.
> >
> >> There's an obvious clock skew problem on Windows 7; in the Date & Time
> >> dialog, the clock jumps through seconds visibly too fast.
> >>
> >> I also found a case where HPET bugs are causing a real problem: Terraria
> >> (dedicated server) seems to be relying on (something that relies on)
> >> HPET, and QEMU doesn't get it right. The result is a goofy and
> >> aggravating behavior I've nicknamed "Turbo Monsters of Doom" and it
> >> makes killing anything tougher than a normal zombie basically
> >> impossible.
> >>
> >> --
> >> You received this bug notification because you are a member of qemu-
> >> devel-ml, which is subscribed to QEMU.
> >> https://bugs.launchpad.net/bugs/599958
> >>
> >> Title:
> >> Timedrift problems with Win7: hpet missing time drift fixups
> >>
> >> Status in QEMU:
> >> Confirmed
> >>
> >> Bug description:
> >> We've been finding timedrift issues witth Win7 under qemu-kvm on our
> >> daily testing
> >>
> >> kvm.qemu-kvm-git.smp2.Win7.64.timedrift.with_load FAIL 1 Time
> >> drift too large after rest period: 38.63%
> >> kvm.qemu-kvm-git.smp2.Win7.64.timedrift.with_reboot FAIL 1 Time
> >> drift too large at iteration 1: 17.77 seconds
> >> kvm.qemu-kvm-git.smp2.Win7.64.timedrift.with_migration FAIL 1
> >> Time drift too large at iteration 2: 3.08 seconds
> >>
> >> Steps to reproduce:
> >>
> >> timedrift.with_load
> >>
> >> 1) Log into a guest.
> >> 2) Take a time reading from the guest and host.
> >> 3) Run load on the guest and host.
> >> 4) Take a second time reading.
> >> 5) Stop the load and rest for a while.
> >> 6) Take a third time reading.
> >> 7) If the drift immediately after load is higher than a user-
> >> specified value (in %), fail.
> >> If the drift after the rest period is higher than a user-specified
> >> value,
> >> fail.
> >>
> >> timedrift.with_migration
> >>
> >> 1) Log into a guest.
> >> 2) Take a time reading from the guest and host.
> >> 3) Migrate the guest.
> >> 4) Take a second time reading.
> >> 5) If the drift (in seconds) is higher than a user specified value, fail.
> >>
> >> timedrift.with_reboot
> >>
> >> 1) Log into a guest.
> >> 2) Take a time reading from the guest and host.
> >> 3) Reboot the guest.
> >> 4) Take a second time reading.
> >> 5) If the drift (in seconds) is higher than a user specified value, fail.
> >>
> >> This bug is to register those issues and keep an eye on them.
> >>
> >> Attached, some logs from the autotest tests executed on the guest
> >>
> >> To manage notifications about this bug go to:
> >> https://bugs.launchpad.net/qemu/+bug/599958/+subscriptions
> >
> > --
> > Gleb.
--
Gleb.