[Users] Dstat plugin for OpenVZ CPU statistics

[Kirill Korotaev]

Dag,

I think the following statistics are helpful for OpenVZ:

- per VE UBC fail counters (failcnt in /proc/user_beancounters).
  I would draw a delta between 2 screen updates and if it is non-zero
  draw it in red.
- per VE memory limit (kmemsize + privvmpages) and current usage
  (kmemsize + oomguarpages). Same, if kmemsize or privvmpages
  failcnt is increasing, then it can be drawn in red.
- per VE CPU usage. This one can be calculated from /proc/fairsched2
  here are some details on this:
  http://forum.openvz.org/index.php?t=tree&th=479&mid=2771&&rev=&reveal=
- per VE and global CPU and memory latency.

- per VE disk I/O stats (stats not available yet).
- per VE network stats (there is no generic stats yet).

Thanks,
Kirill

> Dag,
> 
> Thank you! I actually use dstat on my Gentoo note.
> 
> Speaking of counters, /proc/user_beancounters is of interest to any 
> OpenVZ user. Format is described at 
> http://wiki.openvz.org/proc/user_beancounters. "held" and "failcnt" 
> columns are most "dynamic". You can use the values either directly, or 
> make some consolidated figures based of formulae in wiki.
> 
> Other thing that might be of interest is /proc/fairsched{,2}. These 
> files are from OpenVZ Fair CPU scheduler. The only problem is looks like 
> the format is not documented (well, not counting the source code).
> 
> Also, Kirill Korotaev will give us some suggestions...
> 
> Dag Wieers wrote:
> 
>>Hi,
>>
>>I've just written a small dstat plugin to monitor CPU usage per VE. You 
>>can find the plugin in the dstat subversion repository linked from:
>>
>>	http://dag.wieers.com/home-made/dstat/
>>
>>Dstat is much like vmstat, but modular and versatile. So you can extend it 
>>with whatever counters you want to visualize, next to other counters. This 
>>helps to relate counters and find/troubleshoot bottlenecks.
>>
>>This plugin can help to find the most consuming VE, or visualize how VE's 
>>are matching up to each other (and the system CPU usage).
>>
>>I don't know whether the nice-value in /proc/vz/vestat is ever used (maybe 
>>I shouldn't add it in the list of counters).
>>
>>I also don't know what other information in /proc/vz would be interesting 
>>to vizualise (over a timeframe). I'm willing to add more plugins in dstat 
>>for openvz if I know how to make more sense of the current counters (and 
>>their usefulness). Feedback from developers welcome :)
>>
>>Visually it looks like this (without colors though):
>>
>>[root at itmphys01 dstat]# ./dstat -M cpu,vz -f 5
>>Module dstat_vz is still experimental.
>>-------cpu0-usage--------------cpu1-usage------ --ve-301-usage----ve-302-usage-
>>usr sys idl wai hiq siq:usr sys idl wai hiq siq|usr sys idl nic:usr sys idl nic
>>  0   0  99   0   0   0:  0   0  99   1   0   0|  0   0 100   0:  0   0 100   0
>> 25  15  50  10   0   0:  1   1  76  22   0   1| 26  15  60   0:  0   0 100   0
>> 31  18  12  40   0   0:  2   2  70  25   0   1| 33  19  49   0:  0   0 100   0
>> 16  14  35  35   0   0:  0   1  53  46   0   0| 16  14  70   0:  0   0 100   0
>>  5   5  59  30   0   0: 16  28  30  26   0   0| 20  32  47   0:  0   0 100   0
>>  0   0 100   0   0   0:  3   5  88   5   0   0|  2   5  93   0:  0   0 100   0
>>  0   0  98   1   0   0:  0   0  99   1   0   0|  0   0 100   0:  0   0 100   0
>>  0   0 100   0   0   0:  0   0  98   1   0   0|  0   0 100   0:  0   0 100   0
>>  0   0  96   4   0   0:  0   3  97   0   0   0|  0   0 100   0:  0   0 100   0
>>
>>[root at itmphys01 dstat]# ./dstat -M cpu,vz -C total -f 5
>>Module dstat_vz is still experimental.
>>----total-cpu-usage---- --ve-301-usage----ve-302-usage-
>>usr sys idl wai hiq siq|usr sys idl nic:usr sys idl nic
>>  0   0  99   1   0   0|  0   0 100   0:  0   0 100   0
>>  0   0  97   2   0   0|  0   0 100   0:  0   0 100   0
>> 19  12  61   8   0   0| 37  23  40   0:  0   0 100   0
>> 12   8  41  38   0   0| 25  15  61   0:  0   0 100   0
>> 14  14  35  37   0   0| 28  26  46   0:  0   0 100   0
>>  4  10  84   3   0   0|  7  20  73   0:  0   0 100   0
>>  0   0  99   1   0   0|  0   0 100   0:  0   0 100   0
>>  0   0  99   1   0   0|  0   0 100   0:  0   0 100   0
>>  0   0  99   1   0   0|  0   0 100   0:  0   0 100   0
>>  0   0 100   0   0   0|  0   0 100   0:  0   0 100   0
>>
>>All feedback welcomed.
>>
>>Kind regards,
>>--   dag wieers,  dag at wieers.com,  http://dag.wieers.com/   --
>>[all I want is a warm bed and a kind word and unlimited power]
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>>  
> 
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