[jira] [Commented] (HBASE-3759) Eliminate use of ThreadLocals for CoprocessorEnvironment bypass() and complete()
[ https://issues.apache.org/jira/browse/HBASE-3759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13019518#comment-13019518 ] Hudson commented on HBASE-3759: --- Integrated in HBase-TRUNK #1850 (See [https://hudson.apache.org/hudson/job/HBase-TRUNK/1850/]) Eliminate use of ThreadLocals for CoprocessorEnvironment bypass() and complete() Key: HBASE-3759 URL: https://issues.apache.org/jira/browse/HBASE-3759 Project: HBase Issue Type: Improvement Components: coprocessors Reporter: Gary Helmling Assignee: Gary Helmling Fix For: 0.92.0 Attachments: HBASE-3759.patch, cp_bypass.tar.gz In the current coprocessor framework, ThreadLocal objects are used for the bypass and complete booleans in CoprocessorEnvironment. This allows the *CoprocessorHost implementations to identify when to short-circuit processing the the preXXX and postXXX hook methods. Profiling the region server, however, shows that these ThreadLocals can become a contention point when on a hot code path (such as prePut()). We should refactor the CoprocessorHost pre/post implementations to remove usage of the ThreadLocal variables and replace them with locally scoped variables to eliminate contention between handler threads. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (HBASE-3759) Eliminate use of ThreadLocals for CoprocessorEnvironment bypass() and complete()
[ https://issues.apache.org/jira/browse/HBASE-3759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13019676#comment-13019676 ] jirapos...@reviews.apache.org commented on HBASE-3759: -- --- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/588/#review458 --- src/main/java/org/apache/hadoop/hbase/coprocessor/ObserverContext.java https://reviews.apache.org/r/588/#comment885 First, please let me know if i am thinking in the right direction: In the threadlocal version, we are setting it to false because this variable is shared by the registered CPs in all their pre/postXXX hooks, and it was used to decide whether to continue with the CP chain or return from the currently executing CP. So, to reuse this variable, it was set to false again. If that is the case, in this version, we are having a separate instance of ObserverContext for one hook, and i don't see that we need to reset these variables. The same goes with the current variable. Am i getting it right? (I want to come up with a CP observer for 3607, therefore want to grok it a bit, hope you don't mind) Thanks. - himanshu On 2011-04-13 01:08:50, Gary Helmling wrote: bq. bq. --- bq. This is an automatically generated e-mail. To reply, visit: bq. https://reviews.apache.org/r/588/ bq. --- bq. bq. (Updated 2011-04-13 01:08:50) bq. bq. bq. Review request for hbase. bq. bq. bq. Summary bq. --- bq. bq. Profiling the HRegionServer process with a RegionObserver coprocessor loaded shows a fair amount of runnable thread CPU time spent getting the bypass and complete flag ThreadLocal values by RegionCoprocessorHost. See the HBASE-3759 JIRA for some attached graphs. bq. bq. With the caveat that this is runnable CPU time and not threads in all states, this still seems like a significant processing bottleneck on a hot call path. The workload profiled was a put-based bulk load, so for each multi-put request, RegionCoprocessorHost.prePut() could be called many times. bq. bq. Instead of using ThreadLocal variable for bypass/complete, which will incur contention on the underlying map of values, I think we can eliminate the bottleneck by using locally scoped variables for each preXXX/putXXX method called in the RegionCoprocessorHost, MasterCoprocessorHost and WALCoprocessorHost classes. bq. bq. The attached patch refactors the current RegionObserver, MasterObserver and WALObserver APIs to provide a locally scoped ObserverContext object for storing and checking the bypass and complete values. bq. bq. Summary of changes: bq. bq. * adds a new ObserverContextT extends CoprocessorEnvironment class, containing references for bypass, complete and the environment instance bq. * in each pre/post method in RegionObserver, the RegionCoprocessorEnvironment parameter is replaced by ObserverContextRegionCoprocessorEnvironment bq. * in each pre/post method in MasterObserver, the MasterCoprocessorEnvironment parameter is replaced by ObserverContextMasterCoprocessorEnvironment bq. * in each pre/post method in WALObserver, the WALCoprocessorEnvironment parameter is replace by ObserverContextWALCoprocesorEnvironment bq. bq. bq. This is obviously a large bulk change to the existing API. I could avoid the API change with hacky modification underneath the *CoprocessorEnvironment interfaces. But since we do not yet have a public release with coprocessors, I would prefer to take the time to make the initial API the best we can before we push it out. bq. bq. Please let me know your thoughts on this approach. bq. bq. bq. This addresses bug HBASE-3759. bq. https://issues.apache.org/jira/browse/HBASE-3759 bq. bq. bq. Diffs bq. - bq. bq. src/main/java/org/apache/hadoop/hbase/coprocessor/BaseMasterObserver.java 9576c48 bq. src/main/java/org/apache/hadoop/hbase/coprocessor/BaseRegionObserverCoprocessor.java 5a0f095 bq. src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorEnvironment.java d45b950 bq.src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorHost.java a82f62b bq.src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java db0870b bq.src/main/java/org/apache/hadoop/hbase/coprocessor/ObserverContext.java PRE-CREATION bq.src/main/java/org/apache/hadoop/hbase/coprocessor/RegionObserver.java 3501958 bq.src/main/java/org/apache/hadoop/hbase/coprocessor/WALObserver.java 7a34d18 bq.src/main/java/org/apache/hadoop/hbase/master/MasterCoprocessorHost.java 019bbde bq.
[jira] [Commented] (HBASE-3759) Eliminate use of ThreadLocals for CoprocessorEnvironment bypass() and complete()
[ https://issues.apache.org/jira/browse/HBASE-3759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13019172#comment-13019172 ] jirapos...@reviews.apache.org commented on HBASE-3759: -- --- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/588/#review434 --- Ship it! +1 Looks good Gary. Agree do it now before 0.92. By chance did you see if it made a difference profiling? - Michael On 2011-04-13 01:08:50, Gary Helmling wrote: bq. bq. --- bq. This is an automatically generated e-mail. To reply, visit: bq. https://reviews.apache.org/r/588/ bq. --- bq. bq. (Updated 2011-04-13 01:08:50) bq. bq. bq. Review request for hbase. bq. bq. bq. Summary bq. --- bq. bq. Profiling the HRegionServer process with a RegionObserver coprocessor loaded shows a fair amount of runnable thread CPU time spent getting the bypass and complete flag ThreadLocal values by RegionCoprocessorHost. See the HBASE-3759 JIRA for some attached graphs. bq. bq. With the caveat that this is runnable CPU time and not threads in all states, this still seems like a significant processing bottleneck on a hot call path. The workload profiled was a put-based bulk load, so for each multi-put request, RegionCoprocessorHost.prePut() could be called many times. bq. bq. Instead of using ThreadLocal variable for bypass/complete, which will incur contention on the underlying map of values, I think we can eliminate the bottleneck by using locally scoped variables for each preXXX/putXXX method called in the RegionCoprocessorHost, MasterCoprocessorHost and WALCoprocessorHost classes. bq. bq. The attached patch refactors the current RegionObserver, MasterObserver and WALObserver APIs to provide a locally scoped ObserverContext object for storing and checking the bypass and complete values. bq. bq. Summary of changes: bq. bq. * adds a new ObserverContextT extends CoprocessorEnvironment class, containing references for bypass, complete and the environment instance bq. * in each pre/post method in RegionObserver, the RegionCoprocessorEnvironment parameter is replaced by ObserverContextRegionCoprocessorEnvironment bq. * in each pre/post method in MasterObserver, the MasterCoprocessorEnvironment parameter is replaced by ObserverContextMasterCoprocessorEnvironment bq. * in each pre/post method in WALObserver, the WALCoprocessorEnvironment parameter is replace by ObserverContextWALCoprocesorEnvironment bq. bq. bq. This is obviously a large bulk change to the existing API. I could avoid the API change with hacky modification underneath the *CoprocessorEnvironment interfaces. But since we do not yet have a public release with coprocessors, I would prefer to take the time to make the initial API the best we can before we push it out. bq. bq. Please let me know your thoughts on this approach. bq. bq. bq. This addresses bug HBASE-3759. bq. https://issues.apache.org/jira/browse/HBASE-3759 bq. bq. bq. Diffs bq. - bq. bq. src/main/java/org/apache/hadoop/hbase/coprocessor/BaseMasterObserver.java 9576c48 bq. src/main/java/org/apache/hadoop/hbase/coprocessor/BaseRegionObserverCoprocessor.java 5a0f095 bq. src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorEnvironment.java d45b950 bq.src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorHost.java a82f62b bq.src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java db0870b bq.src/main/java/org/apache/hadoop/hbase/coprocessor/ObserverContext.java PRE-CREATION bq.src/main/java/org/apache/hadoop/hbase/coprocessor/RegionObserver.java 3501958 bq.src/main/java/org/apache/hadoop/hbase/coprocessor/WALObserver.java 7a34d18 bq.src/main/java/org/apache/hadoop/hbase/master/MasterCoprocessorHost.java 019bbde bq. src/main/java/org/apache/hadoop/hbase/regionserver/RegionCoprocessorHost.java 60efa12 bq. src/main/java/org/apache/hadoop/hbase/regionserver/wal/WALCoprocessorHost.java a3f3b31 bq. src/test/java/org/apache/hadoop/hbase/coprocessor/SampleRegionWALObserver.java 834283f bq. src/test/java/org/apache/hadoop/hbase/coprocessor/SimpleRegionObserver.java 0ce2147 bq. src/test/java/org/apache/hadoop/hbase/coprocessor/TestCoprocessorInterface.java 0db5001 bq. src/test/java/org/apache/hadoop/hbase/coprocessor/TestMasterObserver.java a15d53a bq. src/test/java/org/apache/hadoop/hbase/coprocessor/TestRegionObserverStacking.java 2c1e4a0 bq. bq. Diff: https://reviews.apache.org/r/588/diff bq. bq. bq. Testing bq. --- bq. bq. bq. Thanks, bq. bq. Gary
[jira] [Commented] (HBASE-3759) Eliminate use of ThreadLocals for CoprocessorEnvironment bypass() and complete()
[ https://issues.apache.org/jira/browse/HBASE-3759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13019185#comment-13019185 ] jirapos...@reviews.apache.org commented on HBASE-3759: -- bq. On 2011-04-13 03:23:28, Michael Stack wrote: bq. +1 Looks good Gary. Agree do it now before 0.92. By chance did you see if it made a difference profiling? Yeah if you grab https://issues.apache.org/jira/secure/attachment/12475852/cp_bypass.tar.gz you can see the call trees I grabbed from profiling with the context object (Call_Tree_context_xxx) vs. ThreadLocals (Call_Tree_tl_xxx). If you look at Call_Tree_tl_run.html vs. Call_Tree_context_run.html, you'll see ~20% of the runnable thread time spent in ThreadLocal.get() (under shouldComplete() and shouldBypass()). This is completely eliminated in the context version, though with small overhead for the object instatiation -- 0.4% in CallContext.createAndPrepare(). (This was before a rename of CallContext - ObserverContext). Granted this is only runnable thread time, so it's skewed in terms of overall impact. But at the macro level, the MR put-based import that generated this ran in ~2h15m with the ThreadLocal version, but only ~1h40m with the context version. So seems a pretty substantial improvement. - Gary --- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/588/#review434 --- On 2011-04-13 01:08:50, Gary Helmling wrote: bq. bq. --- bq. This is an automatically generated e-mail. To reply, visit: bq. https://reviews.apache.org/r/588/ bq. --- bq. bq. (Updated 2011-04-13 01:08:50) bq. bq. bq. Review request for hbase. bq. bq. bq. Summary bq. --- bq. bq. Profiling the HRegionServer process with a RegionObserver coprocessor loaded shows a fair amount of runnable thread CPU time spent getting the bypass and complete flag ThreadLocal values by RegionCoprocessorHost. See the HBASE-3759 JIRA for some attached graphs. bq. bq. With the caveat that this is runnable CPU time and not threads in all states, this still seems like a significant processing bottleneck on a hot call path. The workload profiled was a put-based bulk load, so for each multi-put request, RegionCoprocessorHost.prePut() could be called many times. bq. bq. Instead of using ThreadLocal variable for bypass/complete, which will incur contention on the underlying map of values, I think we can eliminate the bottleneck by using locally scoped variables for each preXXX/putXXX method called in the RegionCoprocessorHost, MasterCoprocessorHost and WALCoprocessorHost classes. bq. bq. The attached patch refactors the current RegionObserver, MasterObserver and WALObserver APIs to provide a locally scoped ObserverContext object for storing and checking the bypass and complete values. bq. bq. Summary of changes: bq. bq. * adds a new ObserverContextT extends CoprocessorEnvironment class, containing references for bypass, complete and the environment instance bq. * in each pre/post method in RegionObserver, the RegionCoprocessorEnvironment parameter is replaced by ObserverContextRegionCoprocessorEnvironment bq. * in each pre/post method in MasterObserver, the MasterCoprocessorEnvironment parameter is replaced by ObserverContextMasterCoprocessorEnvironment bq. * in each pre/post method in WALObserver, the WALCoprocessorEnvironment parameter is replace by ObserverContextWALCoprocesorEnvironment bq. bq. bq. This is obviously a large bulk change to the existing API. I could avoid the API change with hacky modification underneath the *CoprocessorEnvironment interfaces. But since we do not yet have a public release with coprocessors, I would prefer to take the time to make the initial API the best we can before we push it out. bq. bq. Please let me know your thoughts on this approach. bq. bq. bq. This addresses bug HBASE-3759. bq. https://issues.apache.org/jira/browse/HBASE-3759 bq. bq. bq. Diffs bq. - bq. bq. src/main/java/org/apache/hadoop/hbase/coprocessor/BaseMasterObserver.java 9576c48 bq. src/main/java/org/apache/hadoop/hbase/coprocessor/BaseRegionObserverCoprocessor.java 5a0f095 bq. src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorEnvironment.java d45b950 bq.src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorHost.java a82f62b bq.src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java db0870b bq.src/main/java/org/apache/hadoop/hbase/coprocessor/ObserverContext.java PRE-CREATION bq.src/main/java/org/apache/hadoop/hbase/coprocessor/RegionObserver.java 3501958 bq.
[jira] [Commented] (HBASE-3759) Eliminate use of ThreadLocals for CoprocessorEnvironment bypass() and complete()
[ https://issues.apache.org/jira/browse/HBASE-3759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13019188#comment-13019188 ] stack commented on HBASE-3759: -- ++1 on commit then (2:15 vs 1:40) Eliminate use of ThreadLocals for CoprocessorEnvironment bypass() and complete() Key: HBASE-3759 URL: https://issues.apache.org/jira/browse/HBASE-3759 Project: HBase Issue Type: Improvement Components: coprocessors Reporter: Gary Helmling Assignee: Gary Helmling Attachments: cp_bypass.tar.gz In the current coprocessor framework, ThreadLocal objects are used for the bypass and complete booleans in CoprocessorEnvironment. This allows the *CoprocessorHost implementations to identify when to short-circuit processing the the preXXX and postXXX hook methods. Profiling the region server, however, shows that these ThreadLocals can become a contention point when on a hot code path (such as prePut()). We should refactor the CoprocessorHost pre/post implementations to remove usage of the ThreadLocal variables and replace them with locally scoped variables to eliminate contention between handler threads. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (HBASE-3759) Eliminate use of ThreadLocals for CoprocessorEnvironment bypass() and complete()
[ https://issues.apache.org/jira/browse/HBASE-3759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13017821#comment-13017821 ] Andrew Purtell commented on HBASE-3759: --- +1 Eliminate use of ThreadLocals for CoprocessorEnvironment bypass() and complete() Key: HBASE-3759 URL: https://issues.apache.org/jira/browse/HBASE-3759 Project: HBase Issue Type: Improvement Components: coprocessors Reporter: Gary Helmling Assignee: Gary Helmling Attachments: cp_bypass.tar.gz In the current coprocessor framework, ThreadLocal objects are used for the bypass and complete booleans in CoprocessorEnvironment. This allows the *CoprocessorHost implementations to identify when to short-circuit processing the the preXXX and postXXX hook methods. Profiling the region server, however, shows that these ThreadLocals can become a contention point when on a hot code path (such as prePut()). We should refactor the CoprocessorHost pre/post implementations to remove usage of the ThreadLocal variables and replace them with locally scoped variables to eliminate contention between handler threads. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
