> On 2012-04-24 20:53:33, Avery Ching wrote: > > http://svn.apache.org/repos/asf/incubator/giraph/trunk/src/main/java/org/apache/giraph/comm/BasicRPCCommunications.java, > > lines 776-777 > > <https://reviews.apache.org/r/4852/diff/1/?file=104059#file104059line776> > > > > Bo, I'm a little leery about converting the List and ArrayList to > > LinkedList and ConcurrentLinkedList. I believe that linked list's will use > > more memory than the array list due to the double links (forward and > > backward). Also, is ConcurrentLinkedList supposted to outperform a > > synchronized ArrayList? I haven't seen much on that. > > > > The concurrenthashmap changes look good.
Avery, thanks for the comments. I just measured the sizes of these classes and below are an estimation. java.util.ArrayList: 149 bytes java.util.LinkedList: 101 bytes java.util.concurrent.ConcurrentLinkedQueue: 118 bytes The tool I was using is a program from the link below. http://www.javapractices.com/topic/TopicAction.do?Id=83 In terms of performance, here is a benchmark. http://www.javacodegeeks.com/2010/09/java-best-practices-queue-battle-and.html In its test #1 (adding element), ConcurrentLinkedQueue performed slightly better than LinkedList. In test #3 (iterator), LinkedList outperformed ConcurrentLinkedQueue. I think the most time consuming part is add, while iteration is also heavily used but no concurrent accesses. - Bo ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4852/#review7185 ----------------------------------------------------------- On 2012-04-24 06:11:38, Bo Wang wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/4852/ > ----------------------------------------------------------- > > (Updated 2012-04-24 06:11:38) > > > Review request for giraph. > > > Summary > ------- > > Use ConcurrentHashMap and ConcurrentLinkedQueue to allow concurrent assess to > message map. The concurrencyLevel of ConcurrentHashMap uses the default > value. There may be some performance gain by tuning this value. > > > This addresses bug GIRAPH-185. > https://issues.apache.org/jira/browse/GIRAPH-185 > > > Diffs > ----- > > > http://svn.apache.org/repos/asf/incubator/giraph/trunk/src/main/java/org/apache/giraph/comm/BasicRPCCommunications.java > 1328747 > > Diff: https://reviews.apache.org/r/4852/diff > > > Testing > ------- > > > Thanks, > > Bo > >
