Re: [Qemu-devel] [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups

[Ben \"Root\" Anderson]

Agh, I forgot reply all.

Seems like something that should be changed, no? It would've saved me
a lot of headache if there was a switch e.g.
-optimize-for=[linux,winxp,
win7,etc] that changed the defaults to be
most accomodating to the specified OS as a guest.

On Tue, Oct 1, 2013 at 11:33 AM, Gleb Natapov <address@hidden> wrote:
> 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.