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Old 04-13-2012, 08:32 AM   #1
andrewhiggs
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Cool Tomcat priority


I am trying to improve the performance of our tomcat6 server. It is running on Ubuntu 11.10.

I think the problem relates to the fact that our cpu is almost always 80% idle. I have tried nicing the proccesses and using cpulimit but nothing seems to make any diferrence. The cpu sits at 80-85% idle and the tomcat application chugs along slowly. A process which takes around 15 minutes on another server (running the cpu at around 80-90% use) takes around 40 minutes here (if it completes before timing out).

Memory usage is good. There is always free RAM on the server (around 6G) and available to Java (Available RAM is normally around 1.4G).

What can I do to get tomcat to use more cpu and ram? Any assistance is truly appreciated. Thanks.

Regards
 
Old 04-13-2012, 08:44 AM   #2
acid_kewpie
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you more than likely want to be inside the JVM, not outside.

http://www.itworld.com/networking/83...ce-tuning-tips
 
Old 04-13-2012, 09:14 AM   #3
andrewhiggs
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Thanks acid_kewpie.

I have gone through this. Nothing really excited me into thinking "that could be it". I did trim down the maxThreads for the connector to 50 (at most about 5 people will be using the application).

The thing that amazes me is this system has no other connections while doing this run. No other applications or services are essentially being used on the machine. Just don't know why the system resources are not being used. Or what they are being spared for.

Regards
 
Old 04-16-2012, 07:29 AM   #4
andrewhiggs
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Hi all,

I am still trying to figure out what is going on here. I have installed cpufrequtils and set both cpu0 and cpu1 to 'performance'. Not much seems to have improved.

I did notice now that every now and then the %wa goes up. Sometimes over 50%. Is this perhaps a disk io issue? Any ideas how I can track down what is causing the waiting? I still feel that either Ubuntu or Tomcat need to be told to use / allow more cpu usage for the processors / threads because the %us peaks at arounf 15%. As stated previously on another machine this runs through in a fraction of the time and %us on that machine runs between 80-90%.

Any clues would be greatly appreciated. Thanks.

Regards
 
Old 04-24-2012, 08:50 AM   #5
andrewhiggs
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Bump.

Still not getting any better. I tried the same application on a quad core processor and it is even worse? How can I tell Ubuntu / Tomcat to use more of the processing power?

Regards
 
Old 05-18-2012, 09:32 AM   #6
andrewhiggs
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Thumbs up

I have installed Ubuntu 12.04 now and the application is running as I would expect. Pity I could not figure out what was wrong (or incorrectly configured) on other systems.

Thanks to all those who helped.

Regards
 
  


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