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From "Pete Clark" <peter.r.cl...@gmail.com>
Subject Re: large-scale app.. random spiking on even static files!
Date Sat, 09 Aug 2008 04:09:20 GMT
Finally, here are our startup opts as it pertains to GC if it helps:

-XX:+HeapDumpOnOutOfMemoryError -XX:PermSize=256m -XX:MaxPermSize=256m
-Xmx5120m -Xms5120m -Xss128k -XX:ParallelGCThreads=20
-XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:SurvivorRatio=8
-XX:TargetSurvivorRatio=90 -XX:MaxTenuringThreshold=31
-XX:+AggressiveOpts -Xloggc:/var/tmp/gc.log

On Fri, Aug 8, 2008 at 11:59 PM, pc3 <peter.r.clark@gmail.com> wrote:
>
> Oh yeah, and we're using tomcat as the servlet engine.. thanks!
>
>
> pc3 wrote:
>>
>> hey all -
>>
>> so i've spent the past two weeks trying to figure out why my large scale
>> application (200m page views per month) is having some serious, yet
>> random, spikes in response times.
>>
>> we've got an app running under gero 1.1.1, using hibernate, mysql, etc.
>> i've got the response times down in general by adding memcaching and other
>> optimizations but we still see the spikes.. e.g. most of our actions
>> return in 0.1 sec, but occasionally (and often enough!) .. we'll see a
>> random spike up to 30s from different machines in our cluster.
>>
>> so for kicks tonight i tried running a test against all of our app servers
>> not for an action but for a plain .txt file ... and guess what... spiky
>> responses just from the txt file!  a 4.9kb text file!  look:
>>
>> $profileUrl /blah/Languages.txt
>> Host 192.168.1.100
>> Time taken for tests:   8.555825 seconds <<<<<<<<<<<<
>> Host 192.168.1.101
>> Time taken for tests:   0.2064 seconds
>> Host 192.168.1.108
>> Time taken for tests:   0.1436 seconds
>> Host 192.168.1.104
>> Time taken for tests:   0.1667 seconds
>> Host 192.168.1.112
>> Time taken for tests:   0.1444 seconds
>> Host 192.168.1.117
>> Time taken for tests:   0.4575 seconds
>> Host 192.168.1.118
>> Time taken for tests:   0.2015 seconds
>> Host 192.168.1.119
>> Time taken for tests:   0.2003 seconds
>> Host 192.168.1.120
>> Time taken for tests:   0.1713 seconds
>> Host 192.168.1.121
>> Time taken for tests:   7.22861 seconds <<<<<<<<<<<<
>> Host 192.168.1.122
>> Time taken for tests:   0.1615 seconds
>>
>> Here are some things to go on:
>> 1) we still host a few swfs from these servers that are hit frequently.
>> could these be causing some kind of blocking?
>> 2) we have a method in our application that acts as a proxy, taking a url
>> as a parameter, fetching the url then dumping it to the response
>>
>> I'm open to any ideas or suggestions as to what could be causing the
>> spikiness of response times here for a txt file.. one that never even hits
>> our java code.
>>
>> Thanks very much all...
>>
>>
>
> --
> View this message in context: http://www.nabble.com/large-scale-app..-random-spiking-on-even-static-files%21-tp18902003s134p18902031.html
> Sent from the Apache Geronimo - Users mailing list archive at Nabble.com.
>
>

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