This page is a place for Michael to dump his frequent rants and notes on improving build performance.
There hasn't as yet been a lot of work done in tuning this process for performance. Some improvements have been made in the compiler, and using MVEL can yield good results.
The problem areas:
Compiling (parsing is very fast)
Rete network building
Serialization/deserialization of binary assets
There is a utility class LargeRuleBase which provides the ability to generate large numbers of complex rules for profiling.
Its results (so far) for 20K complex rules:
Time taken for parsing: 6264
Time taken for compiling: 168864
Time taken rete building: 968571
Time taken serializing rulebase: 42739