[ovirt-users] ovirt-ha-agent cpu usage

[Michal Skrivanek]

> On 7 Oct 2016, at 15:28, Simone Tiraboschi <stirabos at redhat.com> wrote:
> 
> 
> 
> On Fri, Oct 7, 2016 at 3:25 PM, Michal Skrivanek <michal.skrivanek at redhat.com <mailto:michal.skrivanek at redhat.com>> wrote:
> 
>> On 7 Oct 2016, at 14:59, Nir Soffer <nsoffer at redhat.com <mailto:nsoffer at redhat.com>> wrote:
>> 
>> On Fri, Oct 7, 2016 at 3:52 PM, Michal Skrivanek <michal.skrivanek at redhat.com <mailto:michal.skrivanek at redhat.com>> wrote:
>> 
>>> On 7 Oct 2016, at 14:42, Nir Soffer <nsoffer at redhat.com <mailto:nsoffer at redhat.com>> wrote:
>>> 
>>> On Wed, Oct 5, 2016 at 1:33 PM, Simone Tiraboschi <stirabos at redhat.com <mailto:stirabos at redhat.com>> wrote:
>>> 
>>> 
>>> On Wed, Oct 5, 2016 at 10:34 AM, Nir Soffer <nsoffer at redhat.com <mailto:nsoffer at redhat.com>> wrote:
>>> On Wed, Oct 5, 2016 at 10:24 AM, Simone Tiraboschi <stirabos at redhat.com <mailto:stirabos at redhat.com>> wrote:
>>> 
>>> 
>>> On Wed, Oct 5, 2016 at 9:17 AM, gregor <gregor_forum at catrix.at <mailto:gregor_forum at catrix.at>> wrote:
>>> Hi,
>>> 
>>> did you found a solution or cause for this high CPU usage?
>>> I have installed the self hosted engine on another server and there is
>>> no VM running but ovirt-ha-agent uses heavily the CPU.
>>> 
>>> Yes, it's due to the fact that ovirt-ha-agent periodically reconnects over json rpc and this is CPU intensive since the client has to parse the yaml API specification each time it connects.
>> 
>> wasn’t it suppose to be fixed to reuse the connection? Like all the other clients (vdsm migration code:-) 
>> 
>> This is orthogonal issue.
> 
> Yes it is. And that’s the issue;-)
> Both are wrong, but by “fixing” the schema validation only you lose the motivation to fix the meaningless wasteful reconnect
> 
> Yes, we are going to fix that too ( https://bugzilla.redhat.com/show_bug.cgi?id=1349829 <https://bugzilla.redhat.com/show_bug.cgi?id=1349829> )

that’s great! Also al the other vdsClient uses?:-)
What is that periodic one call anyway? Is there only one? Maybe we don’t need it so much.

> but it would require also https://bugzilla.redhat.com/show_bug.cgi?id=1376843 <https://bugzilla.redhat.com/show_bug.cgi?id=1376843> to be fixed.

This is less good. Well, worst case you can reconnect yourself, all you need is a notification when the existing connection breaks

>  
> 
>>  
>> Does schema validation matter then if there would be only one connection at the start up?
>> 
>> Loading once does not help command line tools like vdsClient, hosted-engine and
>> vdsm-tool. 
> 
> none of the other tools is using json-rpc.
> 
> hosted-engine-setup is, and sooner or later we'll have to migrate also the remaining tools since xmlrpc has been deprecated with 4.0

ok. though setup is a one-time action so it’s not an issue there

>  
> 
>> 
>> Nir
>>  
>> 
>>> 
>>> Simone, reusing the connection is good idea anyway, but what you describe is 
>>> a bug in the client library. The library does *not* need to load and parse the
>>> schema at all for sending requests to vdsm.
>>> 
>>> The schema is only needed if you want to verify request parameters,
>>> or provide online help, these are not needed in a client library.
>>> 
>>> Please file an infra bug about it.
>>> 
>>> Done, https://bugzilla.redhat.com/show_bug.cgi?id=1381899 <https://bugzilla.redhat.com/show_bug.cgi?id=1381899>
>>> 
>>> Here is a patch that should eliminate most most of the problem:
>>> https://gerrit.ovirt.org/65230 <https://gerrit.ovirt.org/65230>
>>> 
>>> Would be nice if it can be tested on the system showing this problem.
>>> 
>>> Cheers,
>>> Nir
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>> 
>> 
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