Clément,
Thanks for addressing my concerns! See comments below.
Clément Calmels wrote:
Hi,
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.
Our benchmark framework allows us to use oprofile during test...
couldn't it be better than vmstat?
Good idea.
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.
I agree. Actually, I always try to use 'default' configuration or
installation but I will try to describe the tests in details.
1.3 Would be nice to have diffs between different kernel configs.
The different configs used are available in the lxc site. You will
notice that I used a minimal config file for most of the test, but for
Openvz I had to use the one I found in the OpenVZ site because I faced
kernel build error (some CONFIG_NET... issues).
We are trying to eliminate those, so a bug report would be nice.
I think that the
differences are more dealing with network stuff.
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
I already used this page. I had to increase 'diskinodes' and 'diskspace'
resources in order to run some test properly (the disk errors were more
selfexplicit).
I'm wondering why a default 'guest' creation implies some resources
restrictions? Couldn't the resources be unlimited? I understand the need
for resource management, but the default values look a little bit
tiny...
The reason is security. A guest is untrusted by default, though sane
limits are applied. Same as ulimit which has some sane defaults (check
output of ulimit -a). Same as those kernel settings from /proc/sys --
should /proc/sys/fs/file-max be 'unlimited' by default?
In fact, those limits are taken from a sample configuration file during
"vzctl create" stage. Sample file is specified in global OpenVZ config
file (/etc/vz/vz.conf, parameter name is CONFIGFILE, default is to take
configuration from /etc/vz/conf/ve-vps.basic.conf-sample).
There are several ways to change that default configuration:
1. (globally) Put another sample config and specify it in /etc/vz/vz.conf
2. (globally) Edit the existing sample config
(/etc/vz/conf/ve-vps.basic.conf-sample)
3. (per VE) Specify another config during vzctl create stage, like this:
vzctl create VEID [--config name]
4. (per VE) Tune the specific parameters using vzctl set [--param value
...] --save
2.2 For OpenVZ specifically, it would be nice to collect
/proc/user_beancounters output before and after the test.
For sure... I will take a look at how integrating it in our automatic
test environment.
Best regards,
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