Execution groups and thread instances
An execution group is an operating system process, that can host multiple message flows. Each message flow can be allocated additional thread instances. When scaling it is usual to ponder how many execution groups should be used and how many thread instances to add. As a general guide, benchmark tests of FTM have shown linear scalability up to about 6 threads of execution per message flow within an execution group. Above 6 threads scalability is still present but it becomes less linear. For this reason it is generally recommended that you generally plan to have 6-10 threads of execution per execution group.