Tomcat using only 1 cpu

[Landon Fabbricino <lf...@agrium.com>]

Hello,

We have been experiencing an issue where tomcat (jsvc) is only
utilizing one CPU rather then the four available.  I happened to notice
that it was only using 1 CPU when the server was slowed to a crawl and
only 25% of the server CPU's (4 of them) was being used.

We have been experiencing this problem on a Sun-Fire-480R Solaris 10
server, 16gb of ram and 4 CPU's.  The server is also using the 64 bit
version of java

Does anyone have any suggestions of what might be causing this problem
? 

Thanks in advance.

Landon Fabbricino
IT Applications

Phone: 403.225.7515
Fax: 403.225.7606
lfabbric@agrium.com


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Re: Tomcat using only 1 cpu

[David Rees <dr...@gmail.com>]

On 7/27/06, Guilherme Silveira <gu...@caelum.com.br> wrote:
> If running CpuTest once gives you 25%.... its a OS/java problem.
> If it gives you 100%... its tomcat's fault...

This particular problem is not likely to be Tomcat's fault, it's most
likely a synchronization/perfromance bug in the application code.

But your test application is a good way to see if the JVM is
multi-threaded or not (any recent JVM should be).

-Dave

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Re: Tomcat using only 1 cpu

[Guilherme Silveira <gu...@caelum.com.br>]

You can probably check if its tomcat's fault or some OS or virtual
machine problem by creating an intensive program to check for 100% cpu
usage:

public class CpuTest {
  public static void main(String[] args) {
    for(int i=0;i<4;i++) new Thread(new Loader()).start();
  }
}
class Loader implements Runnable {
  public void run() {
    while(true);
 }
}

If running CpuTest once gives you 25%.... its a OS/java problem.
If it gives you 100%... its tomcat's fault...

Guilherme

On 7/27/06, Landon Fabbricino <lf...@agrium.com> wrote:
> Hello,
>
> We have been experiencing an issue where tomcat (jsvc) is only
> utilizing one CPU rather then the four available.  I happened to notice
> that it was only using 1 CPU when the server was slowed to a crawl and
> only 25% of the server CPU's (4 of them) was being used.
>
> We have been experiencing this problem on a Sun-Fire-480R Solaris 10
> server, 16gb of ram and 4 CPU's.  The server is also using the 64 bit
> version of java
>
> Does anyone have any suggestions of what might be causing this problem
> ?
>
> Thanks in advance.
>
> Landon Fabbricino
> IT Applications
>
> Phone: 403.225.7515
> Fax: 403.225.7606
> lfabbric@agrium.com
>
>
>                             IMPORTANT NOTICE !
> This E-Mail transmission and any accompanying attachments may contain
> confidential information intended only for the use of the individual or
> entity named above. Any dissemination, distribution, copying or action taken
> in reliance on the contents of this E-Mail by anyone other than the intended
> recipient is strictly prohibited and is not intended to, in anyway, waive
> privilege or confidentiality. If you have received this E-Mail in error please
> immediately delete it and notify sender at the above E-Mail address.
>
> Agrium uses state of the art anti-virus technology on all incoming and
> outgoing E-Mail. We encourage and promote the use of safe E-Mail management
> practices and recommend you check this, and all other E-Mail and attachments
> you receive for the presence of viruses. The sender and Agrium accept no liability
> for any damage caused by a virus or otherwise by the transmittal of this E-Mail.
>                         IMPORTANT NOTICE
>
>
>
>
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> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
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>


-- 
Guilherme Silveira
--------------------------------------------------
guilherme.silveira@caelum.com.br
Caelum - Ensino e Solucoes em Java
www.caelum.com.br

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