RE: [Xen-devel] Re: [PATCH] Align periodic vpts

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

>From: Dan Magenheimer [mailto:dan.magenheimer@xxxxxxxxxx] 
>Sent: Wednesday, February 11, 2009 11:36 PM
>
>> I'm not sure why you count this feature as the cause for guest time
>> inaccuracy. This patch only shifts 1st expiration of 
>periodical timer,
>> and later expirations are all exactly as expected relative 
>to previous
>> one.
>
>OK, if that is correct, I have no problem with the patch.
>
>> VI's issue is not about time inaccuracy or performance, which is
>> about accounting.
>
>Many of the problems (and Oracle has seen customers with similar
>problems) are related to the timing of delivery of "ticks"
>relative to each other, e.g. if consecutive ticks are sometimes
>0.01s apart and sometimes 0.0099s apart and sometimes 0.0101s
>apart, this causes different problems for different guests with
>different default/chosen clocksources.
>

Yep, I agree. It's a common issue from virtualization. :-)

Thanks,
Kevin
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