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From Peter Buning <bun...@kicktipp.de>
Subject Re: few slow requests
Date Wed, 04 Aug 2010 07:33:41 GMT
Hi Chris,

Am 03.08.2010 22:08, schrieb Christopher Schultz:
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> Peter,
>
> On 8/3/2010 10:55 AM, Peter Buning wrote:
>    
>> we tested our tomcat 5.5 server (Debian system) with the apache
>> benchmark tool. We send requests for a small png-file (300 bytes).
>> Nearly all requests were done in 0 or 1 milliseconds. But there were a
>> few request which needed more than 10 ms and the slowest request needed
>> 106 ms.
>>      
> Over what period of time? How often do the 106 and/or 10 responses
> occur? You may be encountering some simple thing like the OS wanting to
> get some of its own work done occasionally.
>    
The slower response times are relative seldom, nearly 0,1 % of the 
requests. I think you are right and the  OS is working "something" in 
this period. I just would like to understand exactly what happens. I 
will continue to search for the reasons in this direction.


>> the 106 ms is logged in the access log file. We used the %D pattern for
>> the request time in millis.
>>
>> It seems not to be a network problem. We can see the same behavior with
>> a remote and a localhost test. Nevertheless, does anybody know, when
>> tomact exactly starts and stop the time for logging the request?
>>      
> The source code for org.apache.catalina.valves.AccessLogValve is
> available here:
>
>    
>> http://svn.apache.org/repos/asf/tomcat/tc5.5.x/tags/TOMCAT_5_5_30/container/catalina/src/share/org/apache/catalina/valves/AccessLogValve.java
>>      
> Look at the "invoke" menu.
>
>    
I will do, thanks.

>> So, we want to know, why there are a few request that took so much more
>> time than the rest of the requests. Has anybody an idea where the time
>> can be consumed?
>>      
> Lots of things are being done by your computer other than running your
> webapp's code. There are lots of things that could be causing temporary
> slowdowns.
>
> - -chris
>    


Thanks for your reply!
Peter


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