Re: sync guest calls made async on host - SQLite performance

[Anthony Liguori <anthony@codemonkey.ws>]

Avi Kivity wrote:
> On 09/24/2009 10:49 PM, Matthew Tippett wrote:
>> The test itself is a simple usage of SQLite.  It is stock KVM as
>> available in 2.6.31 on Ubuntu Karmic.  So it would be the environment,
>> not the test.
>>
>> So assuming that KVM upstream works as expected that would leave
>> either 2.6.31 having an issue, or Ubuntu having an issue.
>>
>> Care to make an assertion on the KVM in 2.6.31?  Leaving only Ubuntu's
>> installation.
>>    
>
> kvm has nothing to do with it, it's purely qemu.  For a long time qemu 
> has defaulted to write-through cacheing.  This can be overridden and 
> maybe that's what Ubuntu or Phoronix do.
>
>> Can some KVM developers attempt to confirm that a 'correctly'
>> configured KVM will not demonstrate this behaviour?
>> http://www.phoronix-test-suite.com/ (or is already available in newer
>> distributions of Fedora, openSUSE and Ubuntu.
>>    
>
> A correctly configured kvm will not demonstrate this behaviour.

It was a very old kvm version (kvm-84).  But of course, the version of 
kvm is not mentioned on the Phoronix site...

Regards,

Anthony Liguori