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

[Matthew Tippett <tippettm@gmail.com>]

(Resending to the list without multi-part).

I now have more information.

Dustin,

The version used was 0.11.0-rc2, from the 2009-09-11 karmic daily build.
  The VM identifies itself as "AMD QEMU Virtual CPU version 0.10.92
stepping 03".

When you indicated that you had attempted to reproduce the problem, what
mechanism did you use?  Was it Karmic + KVM as the host and Karmic as
the guest?  What test did you use?

I will re-open the launchpad bug if you believe it makes sense to
continue the discussions there.

Anthony,

If you can suspend your disbelief for a short while and ask questions to
clarify the details.  My only interest here is to understand the results
presented by the benchmark and determine if there are data integrity risks.

Fundamentally, if there are modes of operation that applications can get
a considerable performance boost by running the same OS under KVM then
there will be lots of people happy.  But realistically it is an
indication of something wrong, misconfigured or just broken it bears at
least some discussion.

Bear in mind that upstream is relevant for KVM, but for distributions
shipping KVM, they may have secondary concerns about patchesets and
upstream changes that may be relevant for how they support their customers.

Regards,

Matthew



-------- Original Message  --------
Subject: Re: sync guest calls made async on host - SQLite performance
From: Anthony Liguori <anthony@codemonkey.ws>
To: Matthew Tippett <tippettm@gmail.com>
Cc: Avi Kivity <avi@redhat.com>, RW <kvm@tauceti.net>, kvm@vger.kernel.org
Date: 09/29/2009 04:51 PM

> Matthew Tippett wrote:
> 
> Your confidence is misplaced apparently.
> 
>> and I have pieced together the following information.  I should be 
>> able to get the actual daily build number but broadly it looks like it 
>> was
>>
>>   Ubuntu 9.10 daily snapshot (~ 9th - 21st September)
>>   Linux 2.6.31 (packaged as 2.6.31-10.30 to 2.6.31-10.32)
>>   qemu-kvm 0.11 (packaged as 0.11.0~rc2-0ubuntu to 0.11.0~rc2-0ubuntu5
> 
> That's extremely unlikely.
> 
>> But, if it turned out to be Ubuntu 9.10, linux 2.6.31, qemu-kvm 0.11 
>> would there be any concerns?
> 
> It's not relevant because it's not qemu-kvm-0.11.