[horde] apache cpu usage?

Thu Feb 18 17:30:18 UTC 2016

Citeren avp at rokeyetee.com:

> Quoting Arjen de Korte <arjen+horde at de-korte.org>:
>
>> Citeren avp at rokeyetee.com:
>>
>>> Quoting Michael J Rubinsky <mrubinsk at horde.org>:
>>>
>>>> Quoting avp at rokeyetee.com:
>>>>
>>>>> I'm running Horde on a AWS t2.medium instance - HORDE GROUPWARE WEBMAIL
>>>>> EDITION 5.2.6
>>>>>
>>>>> I've got some funny apache behaviour that just doesn't seem right to
>>>>> me...
>>>>>
>>>>> When I run "apache2ctl status", 99% of the time all threads are in the
>>>>> "W"
>>>>> (Sending Reply) state:
>>>>>
>>>>>    Current Time: Thursday, 18-Feb-2016 10:02:53 NST
>>>>>    Restart Time: Thursday, 18-Feb-2016 09:49:25 NST
>>>>>    Parent Server Config. Generation: 1
>>>>>    Parent Server MPM Generation: 0
>>>>>    Server uptime: 13 minutes 27 seconds
>>>>>    Server load: 0.77 0.77 0.85
>>>>>    Total accesses: 1382 - Total Traffic: 7.7 MB
>>>>>    CPU Usage: u230.64 s11.47 cu0 cs0 - 30% CPU load
>>>>>    1.71 requests/sec - 9.8 kB/second - 5.7 kB/request
>>>>>    20 requests currently being processed, 8 idle workers
>>>>>  
>>>>> _WWWWWW_WWWWW__W_WWWWWW__W.K_...........
>>>>>
>>>>> It seems strange to me that "sending reply" would be the bottleneck?
>>>>>
>>>>> Also when I run top, I constantly see apache procs jumping to the top
>>>>> with
>>>>> up to 50% cpu usage.
>>>>>
>>>>> Most all the connections are ActiveSync.
>>>>
>>>> When an ActiveSync client is configured for "Push", the connection to
>>>> the webserver remains open while it runs the PING command. These
>>>> requests last up to the "hearbeat interval" that is negotiated between
>>>> the server and client unless there is a change detected, when the PING
>>>> requests ends and a new SYNC request is issued. It makes complete sense
>>>> that you would see ActiveSync connections remaining open.
>>>
>>> Thanks for the quick reply.
>>>
>>> I'm not questioning that the ActiveSync connections remain open -  
>>> I get that.  I'm questioning that the connections are in the  
>>> "Sending Reply" state?  And that my CPU usage seems too high to  
>>> me?  I'm wondering if there is some php being called to generate  
>>> the reply that is being sent but it is taking abnormally  
>>> long/excessive cpu?  Just sort of guessing here...  How might I  
>>> track down what is using the cpu or why the connections are in the  
>>> sending state?
>>>
>>> Here are my activesync settings:
>>>
>>> $conf['activesync']['ping']['heartbeatmin'] = 60;
>>> $conf['activesync']['ping']['heartbeatmax'] = 2700;
>>> $conf['activesync']['ping']['heartbeatdefault'] = 480;
>>> $conf['activesync']['ping']['deviceping'] = true;
>>> $conf['activesync']['ping']['waitinterval'] = 10;
>>>
>>> I just changed waitinterval from 5 to 10.
>>
>> That is still an awfully short interval. It will mean that the PHP  
>> process that is kept active for each device that is connected  
>> through ActiveSync will poll the users mailbox every 10 seconds.  
>> Depending on the number of users you have, this may constitute a  
>> fairly significant load. Note that if you have a decent IMAP server  
>> such a short interval is a waste of effort anyway, as the IMAP  
>> server will notify that things have changed.
>>
>>> Any suggestions on what these should be?
>>
>> If you have a significant number of users connected through  
>> ActiveSync, increase waitinterval to something like 60 seconds (or  
>> more).
>>
>>> Any other tips/advice to lower CPU usage?
>>
>> Which IMAP server are you using and how many ActiveSync devices do  
>> you have connected?
>
> I'm running Dovecot 2.2.9. Are there any Dovecot settings that are  
> recommended?

See http://wiki.dovecot.org/PerformanceTuning

> There are maybe around 30 active ActiveSync connections.

This is not a very high load.

> Currently, apache2ctl status reports 1.94 requests/sec - this number  
> seems nice and low to me - I don't think I should be killing my cpu?
>
> What are others using for wait interval?

I currently use 60 seconds with about 25 concurrent connections at any  
time. But as I wrote earlier, you should decide for yourself  
(basically, based on what your users expect).

> Thanks for the input.
>
>>
>>> Thanks again.
>>>
>>>>
>>>>> What are recommended settings for apache when running Horde?
>>>>>
>>>>> Any other tips/advice to lower CPU usage?  
>>>>> Thanks.
>>>>>
>>>>>  
>>>>> --
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>>>>
>>>> --
>>>> mike
>>>> The Horde Project
>>>> http://www.horde.org
>>>> https://www.facebook.com/hordeprojecthttps://www.twitter.com/hordeproject
>>>
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>>
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