[ https://issues.apache.org/jira/browse/HBASE-20716?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
stack updated HBASE-20716: -------------------------- Fix Version/s: 2.0.3 2.1.1 2.2.0 3.0.0 > Unsafe access cleanup > --------------------- > > Key: HBASE-20716 > URL: https://issues.apache.org/jira/browse/HBASE-20716 > Project: HBase > Issue Type: Sub-task > Components: Performance > Reporter: stack > Assignee: Sahil Aggarwal > Priority: Critical > Labels: beginner > Fix For: 3.0.0, 2.2.0, 2.1.1, 2.0.3 > > Attachments: HBASE-20716.master.001.patch, > HBASE-20716.master.002.patch, HBASE-20716.master.003.patch, > HBASE-20716.master.004.patch, HBASE-20716.master.005.patch, > HBASE-20716.master.006.patch, HBASE-20716.master.007.patch, > HBASE-20716.master.008.patch, Screen Shot 2018-06-26 at 11.37.49 AM.png > > > We have two means of getting at unsafe; UnsafeAccess and then internal to the > Bytes class. They are effectively doing the same thing. We should have one > avenue to Unsafe only. > Many of our paths to Unsafe via UnsafeAccess traverse flags to check if > access is available, if it is aligned and the order in which words are > written on the machine. Each check costs -- especially if done millions of > times a second -- and on occasion adds bloat in hot code paths. The unsafe > access inside Bytes checks on startup what the machine is capable off and > then does a static assign of the appropriate class-to-use from there on out. > UnsafeAccess does not do this running the checks everytime. Would be good to > have the Bytes behavior pervasive. > The benefit of one access to Unsafe only is plain. The benefits we gain > removing checks will be harder to measure though should be plain when you > disassemble a hot-path; in a (very) rare case, the saved byte codes could be > the difference between inlining or not. -- This message was sent by Atlassian JIRA (v7.6.3#76005)