[ https://issues.apache.org/jira/browse/HDFS-6788?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14079913#comment-14079913 ]
Yongjun Zhang commented on HDFS-6788: ------------------------------------- HI [~arpitagarwal], thanks for your help on the other jiras I worked on earlier. I could you could help again on reviewing this one. The fix here is simply to replace the synchronized methods with read write lock, I believe it will hep performance. I did not provide a unit test case here, I wonder whether you think it's really needed after you look at the change. Thanks a lot! > Improve synchronization in BPOfferService with read write lock > -------------------------------------------------------------- > > Key: HDFS-6788 > URL: https://issues.apache.org/jira/browse/HDFS-6788 > Project: Hadoop HDFS > Issue Type: Bug > Components: datanode > Affects Versions: 2.5.0 > Reporter: Yongjun Zhang > Assignee: Yongjun Zhang > Attachments: HDFS-6788.001.patch > > > Threads in DN (DataXceiver, PacketResponder, Async disk worker etc) may block > at BPOfferService.getBlockPoolId() when calling BPOfferService.checkBlock(), > though they are just reading the same blockpool id. This is unnecessary > overhead and may cause performance hit when many threads compete. Filing this > jira to replace synchronized method with read write lock > (ReentrantReadWriteLock). -- This message was sent by Atlassian JIRA (v6.2#6252)