[Engine-devel] Polling vs Pushing engine events

Sven Kieske S.Kieske at mittwald.de
Wed Dec 18 08:07:40 UTC 2013


Hi,

the following seems to be killing our
plans to use a pythonscript to fetch the list of vms:

This comes from the users list:

Am 17.12.2013 15:04, schrieb Sander Grendelman:> Fetching the list of
vms through the API with the python SDK
> takes several seconds[1] with 100% cpu usage in the python script.
>
> When I look at the engine log there is only one (fast) fetch from
> the API. The rest of the time is spent in the SDK processing a
> relatively small bit of XML data (only 26 VMs in my environment).
>
> This seems an excessive amount of CPU for processing ~6KB of XML.
>
> I've included some sample code [2] and output [3].
> Attached is the cProfile output for this call and a visualization.
>
> [1] ~6,5 seconds on an oVirt VM with 1 vcpu on older hardware,
>     ~3,5 seconds on a fast physical machine with an i5 cpu.


Am 17.12.2013 15:31, schrieb Michael Pasternak:>
> Hi Sander,
>
> This is a known issue caused by generateDS python bindings we use,
> it's extremely slow in python<->xml marshalling, and unable to recognize
> cyclic referencing in the objects,
>
> i'm planning to upgrade in 3.4 from 2.9a to 2.12, if it won't help, we may
> consider other options.


This is no option for us at all:

We can't wait for a possible fix in 3.4
(which maybe even does not fix it).

Additionally we will have much higher amounts of vms to query.


-- 
Mit freundlichen Grüßen / Regards

Sven Kieske

Systemadministrator
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