100% CPU usage

[rcgeorge23 <rc...@gmail.com>]

Hi Folks,

Tomcat 5.5
Java 1.5
Hibernate 3.2 (with C3P0 connection pooling)

I'm currently experiencing a problem in our production environment where
Tomcat very quickly consumes 100% of the CPU and doesn't give it back. The
webapp (an ecommerce system) runs absolutely fine on my laptop (inside
Eclipse), so I'm assuming that this is some kind of environmental issue. The
problem begins as soon as a user tries to do something that is momentarily
processor intensive, like performing a search. I would expect the CPU to
peek for a second or so (which it does on my laptop), but I would then
expect the request to be fulfilled and CPU usage to drop back to 0%.
However, CPU usage remains at ~99% until Tomcat is restarted. 

The machine is a P4 3GHz with 1GB of RAM. I have given Tomcat a heap size of
384MB, however it only seems to be consuming about 120MB at most.

I have attached JProfiler to Tomcat in order to try and get an idea of where
the CPU time is being used but sadly I am no wiser. None of my code appears
to be eating CPU time (and neither do any of Tomcat's Java threads).

I'd be really grateful if someone could give me some ideas about how to go
about troubleshooting this.

Cheers,
Richard.
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Re: 100% CPU usage

[rcgeorge23 <rc...@gmail.com>]

Guys,

I've now fixed this. There is a bug in the tcnative-1.dll library that ships
with Tomcat 5.5.17. I realised that if I connected to my webapp on port 8080
(rather than through IIS) everything was fine so I replaced the tcnative
library with version 1.1.8, which you can find here
http://tomcat.heanet.ie/native/1.1.8/binaries/win32/

Hope someone finds this useful!

Cheers.


rcgeorge23 wrote:
> 
> Hi Folks,
> 
> Tomcat 5.5
> Java 1.5
> Hibernate 3.2 (with C3P0 connection pooling)
> 
> I'm currently experiencing a problem in our production environment where
> Tomcat very quickly consumes 100% of the CPU and doesn't give it back. The
> webapp (an ecommerce system) runs absolutely fine on my laptop (inside
> Eclipse), so I'm assuming that this is some kind of environmental issue.
> The problem begins as soon as a user tries to do something that is
> momentarily processor intensive, like performing a search. I would expect
> the CPU to peek for a second or so (which it does on my laptop), but I
> would then expect the request to be fulfilled and CPU usage to drop back
> to 0%. However, CPU usage remains at ~99% until Tomcat is restarted. 
> 
> The machine is a P4 3GHz with 1GB of RAM. I have given Tomcat a heap size
> of 384MB, however it only seems to be consuming about 120MB at most.
> 
> I have attached JProfiler to Tomcat in order to try and get an idea of
> where the CPU time is being used but sadly I am no wiser. None of my code
> appears to be eating CPU time (and neither do any of Tomcat's Java
> threads).
> 
> I'd be really grateful if someone could give me some ideas about how to go
> about troubleshooting this.
> 
> Cheers,
> Richard.
> 

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