Multi CPU Solaris.

Question

Hi,
Is there a recommended number of Weblogic instances when running on a
Multi-CPU machine with more than 8, in this particular case - 28.
The server behaves really bad if I only run one instance there is too
much time spent in the treads waiting to obtain a lock for accessing a
SyncronizedMap (in
webblogic.kernel.ResettableThreadLocal.currentStorage()) and the CPUs
are underutilized.
After a few experiments we found out that 1 instance per 4-6 CPUs is OK,
but I was wondering whether you could recommend something. Also since
there's limit of 2GB per JVM if we wanted to utilize more then there is
no choice.
Thanks,
Deyan
[dejan_bektchiev.vcf]

Answer 1

Yes that what my problem is.
Thanks a lot.
--dejan
Dimitri Rakitine wrote:
It is not a hack - it is a trick ;-) (that's how WLS time services work). I suggested
it because it sounded like you identified synchronization contention caused by using
non-WebLogic threads in your application.
Deyan D. Bektchiev <[email protected]> wrote:
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Dimitri,
Is this supported or is it really a hack?
Because I could still run multiple JVMs and when we want to utilize more memory we
are forced to do that anyway as the limit is just below 2GB/JVM and if you have even
16GB that already automatically means 7-8 JVMs which usually does the trick.
Thanks,
Deyan
Dimitri Rakitine wrote:
If using non-WebLogic threads is an immediate problem, you can try to use
this hack: http://dima.dhs.org/misc/LongRunningTask.jsp (MyThread class)
to use WebLogic Execute threads instead of creating your own. (it works
both on 5.1 and 6.0).
Deyan D. Bektchiev <[email protected]> wrote:
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Thanks Adam,
Actually it is true that most of our requests run on non-weblogic threads.
We have a thread pool that runs in the WLS JVM and it is created by a startup
class and afterwards is activated by sending JMS messages to a monitoring
thread that dispatches the requests. The clients connect to a Session EJB and
that session EJB launches the requests and afterwards the clients get their
results via JMS.
We easily support multiple JVMs on one physical server but if it wasn't the
performance hit from accessing that collection we'd prefer to have as few JVMs
as possible as this would also drive down the context switches and the total
number of threads in the system.
All the Best,
Deyan
Adam Messinger wrote:
Deyan,
Can you tell us a bit more about your application. That map in
ResettableThreadLocal shouldn't be hit except for non-WL threads. It is
unusual that this would be a source of contention.
That said, I know of many people who have been successful running multiple
server instances on a single big machine. I think that it is a great
solution if your application is amenable to it.
Cheers!
Adam
"Deyan D. Bektchiev" <[email protected]> wrote in message
news:[email protected]...
Hi,
Is there a recommended number of Weblogic instances when running on a
Multi-CPU machine with more than 8, in this particular case - 28.
The server behaves really bad if I only run one instance there is too
much time spent in the treads waiting to obtain a lock for accessing a
SyncronizedMap (in
webblogic.kernel.ResettableThreadLocal.currentStorage()) and the CPUs
are underutilized.
After a few experiments we found out that 1 instance per 4-6 CPUs is OK,
but I was wondering whether you could recommend something. Also since
there's limit of 2GB per JVM if we wanted to utilize more then there is
no choice.
Thanks,
Deyan
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