Clement,

Thanks for sharing the results! A few comments...

(1) General

1.1 It would be nice to run vmstat (say, vmstat 10) for the duration of the tests, and put the vmstat output logs to the site.

1.2 Can you tell how you run the tests. I am particularly interested in
- how many iterations do you do?
- what result do you choose from those iterations?
- how reproducible are the results?
- are you rebooting the box between the iterations?
- are you reformatting the partition used for filesystem testing?
- what settings are you using (such as kernel vm params)?
- did you stop cron daemons before running the test?
- are you using the same test binaries across all the participants?
- etc. etc...

Basically, the detailed description of a process would be nice to have, in order to catch possible problems. There are a lot of tiny things which are influencing the results. For example, in linux kernels 2.4 binding the NIC IRQ to a single CPU on an SMP system boosts network performance by about 15%! Sure this is not relevant here, it's just an example.

1.3 Would be nice to have diffs between different kernel configs.

(2) OpenVZ specifics

2.1 Concerning the tests running inside an OpenVZ VE, the problem is there is a (default) set of resource limits applied to each VE. Basically one should tailor those limits to suit the applications running, OR, for the purpose of testing, just set those limits to some very high values so they will never be reached.

For example, the tbench test is probably failed to finish because it hits the limits for privvmpages, tcpsndbuf and tcprcvbuf. I have increased the limits for those parameters and the test was finished successfully. Also, dbench test could hit the disk quota limit for a VE.

Some more info is available at http://wiki.openvz.org/Resource_management

2.2 For OpenVZ specifically, it would be nice to collect /proc/user_beancounters output before and after the test.

Clément Calmels wrote:
Hi,

A first round about virtualisation benchmarks can be found here:
http://lxc.sourceforge.net/bench/
These benchmarks run with vanilla kernels and the patched versions of
well know virtualisation solutions: VServer and OpenVZ. Some benchs also
run inside the virtual 'guest' but we ran into trouble trying to run
some of them... probably virtual 'guest' configuration issues... we will
trying to fix them...
The metacluster migration solution (formely a Meiosys company produt)
was added as it seems that the checkpoint/restart topic is close to the
virtualisation's one (OpenVZ now provides a checkpoint/restart
capability).
For the moment, benchmarks only ran on xeon platform but we expect more
architecture soon. Besides the 'classic' benchs used, more network
oriented benchs will be added. Netpipe between two virtual 'guests' for
example. We hope we will be able to provide results concerning the
virtual 'guest' scalability, running several 'guest' at the same time.

Best regards,


Le mercredi 07 juin 2006 à 16:20 +0200, Clement Calmels a écrit :
Hello !

I'm part of a team of IBMers working on lightweight containers and we
are going to start a new test campaign. Candidates are vserver,
vserver context, namespaces (being pushed upstream), openvz, mcr (our
simple container dedicated to migration) and eventually xen.

We will focus on the performance overhead but we are also interested in
checkpoint/restart and live migration. A last topic would be how well
the
resource managment criteria are met, but that's extra for the moment.

We plan on measuring performance overhead by comparing the results on
a vanilla kernel with a partial and with a complete virtual
environment. By partial, we mean the patched kernel and a 'namespace'
virtualisation.

Test tools
----------
o For network performance :

 * netpipe (http://www.scl.ameslab.gov/netpipe/)
 * netperf (http://www.netperf.org/netperf/NetperfPage.html)
 * tbench (http://samba.org/ftp/tridge/dbench/README)

o Filesystem :

  * dbench (http://samba.org/ftp/tridge/dbench/README)
  * iozone (http://www.iozone.org/)

o General

  * kernbench (http://ck.kolivas.org/kernbench/) stress cpu and
    filesystem through kernel compilation
  * More 'real world' application could be used, feel free to submit
    candidates...

We have experience on C/R and migration so we'll start with our own
scenario, migrating oracle under load. The load is generated by DOTS
(http://ltp.sourceforge.net/dotshowWe ran into trouble trying to run sto.php).

If you could provided us some material on what has already been done :
URL, bench tools, scenarios. We'll try to compile them in. configuration
hints and tuning are most welcome if they are reasonable.

Results, tools, scenarios will be published on lxc.sf.net . We will
set up the testing environment so as to be able to accept new
versions, patches, test tools and rerun the all on demand. Results,
tools, scenarios will be published on lxc.sf.net.

thanks !

Clement,

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