Walter Su created HADOOP-12475: ---------------------------------- Summary: Replace guava Cache with ConcurrentHashMap for caching Connection in ipc Client Key: HADOOP-12475 URL: https://issues.apache.org/jira/browse/HADOOP-12475 Project: Hadoop Common Issue Type: Sub-task Reporter: Walter Su Assignee: Walter Su
quote [~daryn] from HADOOP-11772: {quote} CacheBuilder is obscenely expensive for concurrent map, and it requires generating unnecessary garbage even just to look up a key. Replace it with ConcurrentHashMap. I identified this issue that impaired my own perf testing under load. The slowdown isn't just the sync. It's the expensive of Connection's ctor stalling other connections. The expensive of ConnectionId#equals causes delays. Synch'ing on connections causes unfair contention unlike a sync'ed method. Concurrency simply hides this. {quote} BTW, guava Cache is heavyweight. Per local test, ConcurrentHashMap has better overal performance. -- This message was sent by Atlassian JIRA (v6.3.4#6332)