[infinispan-dev] Concurrent hashmaps parameters

FYI, This might be important for you guys as well (if you haven't done so): I'll add code to configure ConcurrentHashMaps based on system properties, e.g. capacity, load factory etc. This will be important for large clusters. E.g. when we have 1000 nodes in the cluster, most hashmaps in JGroups will contain 1000 entries, and if we only have 16 buckets (the default IIRC), there would be a lot of contention. https://jira.jboss.org/jira/browse/JGRP-1049 ConcurrentHashMap ----------------- CCHMs have a default initial capacity (16), load factor (0.75) and concurrency level (16). These are OK for most scenarios, but we have to investigate whether these values are sufficient for 1000 node clusters. When for example 1000 threads from different senders access the same CCHM, we need to make sure we don't have high contention, ie. by spreading a 1000 senders over 16 buckets. Investigate whether we should add CCHM initial sizes, load factors and concurrency levels as properties. With ergonomics [1], we could for example set bucket sizes for CCHMs dynamically, e.g. based on cluster size. [1] https://jira.jboss.org/jira/browse/JGRP-1037 -- Bela Ban Lead JGroups / Clustering Team JBoss