Comment 11 for bug 599958

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?

On Tue, Oct 1, 2013 at 10:56 AM, Gleb Natapov <email 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.