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

[Matthew Tippett <tippettm@gmail.com>]

Okay, bringing the leafs of the discussions onto this thread.

As per

http://www.phoronix.com/scan.php?page=article&item=linux_2631_kvm&num=1&single=1

"The host OS (as well as the guest OS when testing under KVM) was 
running an Ubuntu 9.10 daily snapshot with the Linux 2.6.31 (final) kernel"

I am attempting to get the actual "daily" snapshot to provide the 
precise version.  I should have that information shortly.  It is likely 
that it was within 1-2 weeks prior to the article posting.


 > Ubuntu's Karmic release has _not_ been released yet.  For this
 > particular test, Phoronix was probably using an alpha drop before
 > Ubuntu switched from kvm-84 to qemu-kvm-0.11.0.

The "probably" was described above - it was a snapshot after the 2.6.31 
final as September 9th, the article was published on September 21st, so 
there is a finite window.

I have high confidence in the testing that Phoronix has done and don't 
expect to need to confirm the results explicitly, 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

Once I get confirmation of the actual date, digger deeping can occur.



But, if it turned out to be Ubuntu 9.10, linux 2.6.31, qemu-kvm 0.11 
would there be any concerns?



I would prefer rather than riling against Phoronix or the results as 
presented, ask questions to seek further information about what was 
tested rather than writing off all of it as completely invalid.

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 03:02 PM

> Matthew Tippett wrote:
>> I have created a launchpad bug against qemu-kvm in Ubuntu.
>>
>> https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/437473
>>
>> Just re-iterating, my concern isn't so much performance, but integrity 
>> of stock KVM configurations with server or other workloads that expect 
>> sync fileIO requests to be honored and synchronous to the underlying 
>> physical disk.
>>
>> (That and ensuring that sanity reigns where a benchmark doesn't show a 
>> guest operating 10 times faster than a host for the same test :).
> 
> And I've closed it.  In the future, please actually reproduce a bug 
> before filing it.  Reading it on a website doesn't mean it's true :-)
> 
> Regards,
> 
> Anthony Liguori