[Users] Loadavg virtualisation problem (028stab047.1+fix)

Kirill Korotaev dev at sw.ru
Sun Nov 18 08:29:00 EST 2007


Dariush,

I would be thankful if you find/provide some exact way
to reproduce it. If not - we will play a bit later and check it.
The issue is not major, it's most likely screw up of process
counters which doesn't affect anything but statistics.

Thanks,
Kirill
P.S. philosophical questions was due to the fact that
   top and similar tools don't show processes which took little
   CPU time and die, thus you can have 100% CPU load and
   top still doesn't show any processes consuming CPU.

Dariush Pietrzak wrote:
> Kirill,
> 
>>1. what kernel do you use?
> 
>  2.6.18 + ovz028stab047.1 
> 
> 
>>2. how do you decide that your machine is idling?
>>   can you please provide output of `ps axf` from HN?
> 
>  this sounds like philosophical question, howether - I created this machine
> for compilation and load testing, so when I'm not loading it with anything,
> it should be idling, and I confirm this with top/munin stats;)
> 
> 
>>3. what do you mean by "I played with adding/removing cpus from the guest"?
>>   vzctl set <VEID> --cpus <N>  or something else?
> 
>  Yes, I started with 8, and then did load testing with varying number of
> cpus, this includes reducing number of cpus while the jobs are running
> (which btw, results in 'top' and similiar tools failing with:
> "top: failed /proc/stat read",  strange that noone noticed this until now)
> 
>  The problem also goes away after I remove limits from number of cpus and
> do some load testing, but this takes multiple hours (and in the meantime
> guest that should be reporting load hovering in 0.2 ~ 1.0 range reported
> load ~ 1500 ).



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