1. Service Demand is the amount of resource spent on a single request. Here we are looking at the CPU service demand which can be arrived with the following formula:
CPU Service Demand = Utilization
Number of Request Served/sec
In the chart 3 we see that the service demand is increasing with increasing load. This is due to the memory contention. Normally for most of the applications the service demand should remain more or less constant with increasing load.
2. We have tried with 2/4/6/8 CPU's and the behavior is very much the same. The effect of increasing load is that all the processors in the system would have threads running in them simultaneously which will bring about this contention.
3. We have tried with JVM 1.4 and the behavior is very much the same.
4. We have also run this on Windows and Solaris platforms. The memory contention remains.