Map/Reduce performance is dependent on cache value size

Performance testing the Map/Reduce changes has shown that the performance improvements vary based on the size of the values in the cache. [1] Using values from 8kB to 128kB shows a large performance increase over Infinispan 6, but smaller and larger values are the same or slower than Infinispan 6.

http://blog.infinispan.org/2014/06/mapreduce-performance-improvements.html