[Jboss-dev-forums] [Design of EJB 3.0] - Contention point in the AOP layer

[<mic...@jb...>]

I cannot seem to be able to drive the CPU load to >85% in my Seam application stress testing. If I increase the client threads, the response time would simply increase and the CPU stays at around 85%. So, I did a thread dump, and found most HTTP threads are waiting at line 161 of class org.jboss.aop.metadata.MethodMetaData. This line is a synchronized access to a HashMap, and it is appreantly a contention point where multiple CPUs have to wait on each other.


  | public class MethodMetaData implements MetaDataResolver {
  | 
  |   public synchronized Object getMethodMetaData(Method method, Object tag, Object attr) {
  | 
  |      // This is line 161:
  |      SimpleMetaData methodData = (SimpleMetaData)methodMetaData.get(method.toString());
  | 
  |   }
  | }
  | 

Clebert suggested to use a concurrent HashMap instead of the method level synchronization here. What do you guys think?

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