One effect that might explain what you describe is garbage collection. If you have 2 instances of tomcat each of them needs less memory than one tomcat handling the same amount of traffic. If you have the same max heap size in both test cases the garbage collection will happen less frequently. If you decrease the heapsize for the two instance test the gc will be faster.
If this is the reason you can try to play with the different gc variants and parameters of the vm. Sun has some background and advice at: http://java.sun.com/docs/hotspot/gc/ http://java.sun.com/products/hotspot/whitepaper.html Also javaworld: http://www.javaworld.com/javaworld/jw-01-2002/jw-0111-hotspotgc.html Another guess is that with two tomcats you get around synchronized code block that serialize request that hit this blocks. (If there is something done in this block that isn't 100% cpu like IO/Database) To verify that you would need a good profiler. If this is the case you can try to reduce the time that is spent in such code blocks. (In your own code and in the tomcat code (Good luck if you try the later)). Third guess: this behaviour could indicate that the thread implementation isn't optimal on your combination of os and vm. Not much chances in this case :( Ralph Einfeldt Uptime Internet Solution Center GmbH Hamburg, Germany Hosting, Content Management, Java Consulting http://www.uptime-isc.de > -----Original Message----- > From: Carlos J. Ramos [mailto:cjramos@;genasys.com] > Sent: Wednesday, October 30, 2002 4:30 PM > To: Tomcat Users List > Subject: Dual tomcat 3.3.1 behaviour. > > > Each test I done outperform old architecture in order of 20%... > > Why? As I think, a dual tomcat configuration must be slower due to > double memory consumption, but figures show me opposite... żis this > normal? żmay I increase the number of java threads, memory... for one > tomcat in order to get the old architecture works as fine as this > "strange" one?.... > -- To unsubscribe, e-mail: <mailto:tomcat-user-unsubscribe@;jakarta.apache.org> For additional commands, e-mail: <mailto:tomcat-user-help@;jakarta.apache.org>
