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From: Avi Kivity <avi@redhat.com>
To: Eran Rom <eranr@il.ibm.com>
Cc: kvm@vger.kernel.org
Subject: Re: guest gettimeofday behavior
Date: Tue, 30 Jun 2009 09:54:29 +0300	[thread overview]
Message-ID: <4A49B6A5.4090801@redhat.com> (raw)
In-Reply-To: <loom.20090629T182016-191@post.gmane.org>

On 06/29/2009 10:11 PM, Eran Rom wrote:
>> Nevertheless, the tsc clock is not reliable,
>> the host can scale it, or
>> go into
>> deep sleep state.
>>      
> indeed my current clock source is tsc
>
>    

You won't get accurate timing with tsc.

>> So either use newer kernel with kvmclock (pv)
>> or change the clock source
>> into rtc/pit
>>
>>      
> No rtc/pit in my available clock sources, however,
> I assume its a question of kernel compilation parameters,
> is that right?
> What is the advantage of rtc/pit/kvmclock (pv)over tsc?
>    

They are accurate.

> Also, is kvmclock (pv) better than the other two options.
>    

Yes.

> the thing is that I am 'confined' to use 2.6.27,
> and if I decide on kvmclock, i will need to add it
> 'manually'
>    

2.6.27 has kvmclock.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.


  reply	other threads:[~2009-06-30  6:54 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-25 13:25 guest gettimeofday behavior Eran Rom
2009-06-28  8:58 ` Dor Laor
2009-06-29 19:11   ` Eran Rom
2009-06-30  6:54     ` Avi Kivity [this message]
2009-06-30  7:48       ` Eran Rom
2009-07-06  8:24         ` Eran Rom
2009-07-07  9:58           ` Eran Rom
2009-07-07 20:12             ` Marcelo Tosatti
2009-07-08 11:51               ` Glauber Costa
2009-07-08 14:07                 ` Eran Rom
2009-07-13  7:55                 ` Eran Rom
2009-07-16  6:24                   ` Eran Rom
2009-06-28 10:45 ` Avi Kivity

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