Re: [PATCH 2/2] Remove -tdf

[Gleb Natapov <gleb@qumranet.com>]

On Tue, Jul 22, 2008 at 08:20:41PM -0500, Anthony Liguori wrote:
>> Currently both in-kernel PIT and even the in kernel irqchips are not  
>> 100% bullet proof.
>> Of course this code is a hack, Gleb Natapov has send better fix for  
>> PIT/RTC to qemu list.
>> Can you look into them:
>> http://www.mail-archive.com/kvm@vger.kernel.org/msg01181.html
>
> Paul Brook's initial feedback is still valid.  It causes quite a lot of  
> churn and may not jive well with a virtual time base.  An advantage to  
> the current -tdf patch is that it's more contained.  I don't think  
> either approach is going to get past Paul in it's current form.
Yes, my patch causes a lot of churn because it changes widely used API.
But the time drift fix itself is contained to PIT/RTC code only. The
last patch series I've sent disables time drift fix if virtual time base
is enabled as Paul requested. There was no further feedback from him.
As Jan Kiszka wrote in one of his mails may be Paul's virtual time base
can be adopted to work with KVM too. BTW how virtual time base handles
SMP guest?

> Also, it's important that this is reproducible in upstream QEMU and not  
> just in KVM.  If we can make a compelling case for the importance of  
> this, we can possibly work out a compromise.
>
I developed and tested my patch with upstream QEMU.

--
			Gleb.