Yes, this is a problem. We call it "virtual hostile". Rob van der Heij
has been doing a tremendous amount of research in this area for the last
4 years, we've been trying to educate our customers (and IBM) on what
this means.
Back in 2001, there was the Linux timer, had the same problem. Got that
fixed. This is the same problem. Only originally because the CPU was
so slow, it was seen as a CPU problem. With much faster CPUs now, this
is a storage problem. There are ways to alleviate the storage problem
in our research. The list of virtually hostile software is quite long.
van Sleeuwen, Berry wrote:
Hi listers,
We have configured a SLES11 SP1 with apache and mono. When we start the
httpd the server is active all the time, keeping it in Q3 all the time.
We have determined that indeed the mono module is the cause for the
wakeup of the guest. Powertop shows that 50%-65% of the time mono was
responsible for wakeup-from-idle and when we remove mono the guest drops
from queue.
We have been looking at some options at this time.
First we have changed KeepAlive too Off in server-tuning.conf, but no
luck.
Next we have created a new configuration for mono in the
/etc/apache2/conf.d directory to replace the default mod_mono.conf.
# note, this config has been created using an online tool to create
configfiles... we added LoadModule and MONO_MANAGED_WATCHER.
LoadModule mono_module /usr/lib64/apache2/mod_mono.so
Alias /sds "/srv/www/htdocs/sds"
MonoServerPath sds "/usr/bin/mod-mono-server2"
MonoSetEnv sds MONO_IOMAP=all;MONO_MANAGED_WATCHER=disable
MonoApplications sds "/sds:/srv/www/htdocs/sds"
<Location "/sds">
Allow from all
Order allow,deny
MonoSetServerAlias sds
SetHandler mono
SetOutputFilter DEFLATE
SetEnvIfNoCase Request_URI "\.(?:gif|jpe?g|png)$" no-gzip dont-vary
</Location>
<IfModule mod_deflate.c>
AddOutputFilterByType DEFLATE text/html text/plain text/xml
text/javascript
</IfModule>
I had found a reference for the MONO_MANAGED_WATCHER that should be set
to disable to prevent mono from watching (polling) for filesystem
updates. But this also has no effect, though I don't know for sure if
this config is really what it should be.
But all this did not yet give us a guest that drops out of queue, it
still remains in Q3. Any ideas what can we do to reduce the activity of
this guest?
Met vriendelijke groet/With kind regards,
Berry van Sleeuwen
Flight Forum 3000 5657 EW Eindhoven
( +31 (0)6 22564276
Atos Origin <http://www.atosorigin.com/>
MO CF SC Mainframe Services
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