The benchmark used was the sqlite subtest in the phoronix test suite.
My awareness and involvement is beyond "reading a magazine article", I
can elaborate if needed, but I don't believe it is necessary.
Process for reproduction, assuming Karmic,
# apt-get install phoronix-test-suite
$ phoronix-test-suite benchmark sqlite
Answer the questions (test-names, etc, etc), it will download sqlite,
build it and execute the test. By default the test runs three timesand
averages the results. The results experienced should be similar to the
values identified at
http://www.phoronix.com/scan.php?page=article&item=linux_2631_kvm&num=3
Which is approximately 12 minutes for the native, and about 60 seconds
for the guest.
Given that the performance under the guest is expected to be around 60
seconds, I would suggest confirming performance there first.
Regards,
Matthew
-------- Original Message --------
Subject: Re: sync guest calls made async on host - SQLite performance
From: Dustin Kirkland <dustin.kirkland@xxxxxxxxx>
To: Matthew Tippett <tippettm@xxxxxxxxx>
Cc: Anthony Liguori <anthony@xxxxxxxxxxxxx>, Avi Kivity
<avi@xxxxxxxxxx>, RW <kvm@xxxxxxxxxxx>, kvm@xxxxxxxxxxxxxxx
Date: 10/07/2009 02:59 PM
On Wed, Oct 7, 2009 at 11:53 AM, Matthew Tippett <tippettm@xxxxxxxxx> wrote:
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 ran the following in several places:
a) on the system running on real hardware,
time dd if=/dev/zero of=$HOME/foo bs=1M count=500
524288000 bytes (524 MB) copied, 9.72614 s, 53.9 MB/s
b) in an vm running on qemu-kvm-0.11 on Karmic
time dd if=/dev/zero of=$HOME/foo bs=1M count=500 oflag=direct
524288000 bytes (524 MB) copied, 31.6961 s, 16.5 MB/s
c) in a vm running on kvm-84 on Jaunty
time dd if=/dev/zero of=$HOME/foo bs=1M count=500 oflag=direct
524288000 bytes (524 MB) copied, 22.2169 s, 23.6 MB/s
Looking at the time it takes to write a 500MB file to a real hard
disk, and then inside of the VM. If I were to experience the problem
on Karmic, I would have seen this dd of a 500MB file take far, far
less time than it takes to write that file to disk on the real
hardware. This was not the case in my testing.
I will re-open the launchpad bug if you believe it makes sense to
continue the discussions there.
Please re-open the bug if you can describe a real test case that you
used to demonstrate the problem. Without being rude, it's hard for me
to work from a bug that says a magazine article says that there's a
bug in the Ubuntu distribution of qemu-kvm-0.11.
If you can provide clear steps that you have used to experience the
problem, then I will be able to take this issue seriously, reproduce
it myself, and develop a fix.
:-Dustin
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