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Hadoop QA commented on HBASE-4714: ---------------------------------- -1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12501789/icms-v2.txt against trunk revision . +1 @author. The patch does not contain any @author tags. -1 tests included. The patch doesn't appear to include any new or modified tests. Please justify why no new tests are needed for this patch. Also please list what manual steps were performed to verify this patch. -1 javadoc. The javadoc tool appears to have generated -166 warning messages. +1 javac. The applied patch does not increase the total number of javac compiler warnings. -1 findbugs. The patch appears to introduce 1 new Findbugs (version 1.3.9) warnings. +1 release audit. The applied patch does not increase the total number of release audit warnings. -1 core tests. The patch failed these unit tests: org.apache.hadoop.hbase.util.TestFSUtils org.apache.hadoop.hbase.master.TestDistributedLogSplitting org.apache.hadoop.hbase.coprocessor.TestCoprocessorEndpoint Test results: https://builds.apache.org/job/PreCommit-HBASE-Build/121//testReport/ Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/121//artifact/trunk/patchprocess/newPatchFindbugsWarnings.html Console output: https://builds.apache.org/job/PreCommit-HBASE-Build/121//console This message is automatically generated. > Don't ship w/ icms enabled by default > ------------------------------------- > > Key: HBASE-4714 > URL: https://issues.apache.org/jira/browse/HBASE-4714 > Project: HBase > Issue Type: Task > Reporter: stack > Assignee: stack > Fix For: 0.92.0 > > Attachments: icms-v2.txt, icms.txt > > > "Incremental CMS (iCMS) was written for a specific use case - 1 or 2 hardware > threads where concurrent activity by CMS would look like a STW (if > only 1 hardware thread) or a high tax on the cpu cycles (2 hardware > threads). It has a higher overhead and also is less efficient in terms > of identifying garbage. The latter is because iCMS spreads out the > concurrent work so that objects that it has identified as live earlier > may actually be dead when the dead objects are swept up. It's > worth testing with regular CMS instead of iCMS." > From recent hotspot mailing list message. > Rare is the case where we run on systems of 1 or 2 hardware threads (other > than fellows laptops and there the above likely doesn't matter). -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira