Hi Alan, This is a bug report with fix. Please review.
webrev: http://cr.openjdk.java.net/~martin/webrevs/openjdk7/EPollArrayWrapper.release/ Synopsis: EPollArrayWrapper.release should be O(N), not O(N^2) Description: In a recent email, I said "no one is really using LinkedList in performance-sensitive production code, eh?" That's completely false, of course. We noticed a server spending 90% of its CPU time in LinkedList.get. That was not really LinkedList's fault, although the changes in 6897553: LinkedList facelift may produce marginal improvements. The real problem is the O(N^2) traversal of the updateList in EPollArrayWrapper. Optimize EPollArrayWrapper.release. Make LinkedList traversal O(N) instead of O(N*N). I'm generally skeptical of the data structures used here, but this change is low-hanging fruit. I'm sure further improvements are possible. My colleague Igor Chernychev has contributed a nice reproduction of this performance problem, included with the fix. Please advise about the best home for this test, and perhaps how to turn it into a "real" jtreg test (which is always hard for performance tests, and especially for those that need network resources). Thanks, Martin
