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From "Andrew Purtell (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-13291) Lift the scan ceiling
Date Sat, 21 Mar 2015 00:02:38 GMT

    [ https://issues.apache.org/jira/browse/HBASE-13291?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14372347#comment-14372347
] 

Andrew Purtell commented on HBASE-13291:
----------------------------------------

A question about this though:
{quote}
export HBASE_OPTS=" -agentpath:/home/stack/lightweight-java-profiler-read-only/build-64/liblagent.so
-XX:+UseConcMarkSweepGC -XX:+UnlockDiagnosticVMOptions -XX:+PrintInlining -XX:+PrintCompilation
-XX:+UnlockCommercialFeatures -XX:+FlightRecorder "
{quote}
Probably should break that up. Maybe you did? 

# Use flight recorder to get event trace data for profiling, IO, monitors, etc. 
# Use the lightweight profiler to get trace files for flame graph visualization
# PrintInlining to get a sense of hot methods and suboptimal inlining
# PrintCompilation with hsdis installed into jre/lib/<plat> or a fastdebug JDK build.

I wouldn't combine them, they'll work at various cross-purposes. Maybe not terribly, but results
will be cleaner IMHO

> Lift the scan ceiling
> ---------------------
>
>                 Key: HBASE-13291
>                 URL: https://issues.apache.org/jira/browse/HBASE-13291
>             Project: HBase
>          Issue Type: Improvement
>          Components: Scanners
>    Affects Versions: 1.0.0
>            Reporter: stack
>            Assignee: stack
>         Attachments: 13291.inlining.txt, q (1).png, traces.7.svg, traces.filterall.svg,
traces.nofilter.svg, traces.smaller.svg
>
>
> Scanning medium sized rows with multiple concurrent scanners exhibits interesting 'ceiling'
properties. A server runs at about 6.7k ops a second using 450% of possible 1600% of CPUs
 when 4 clients each with 10 threads doing scan 1000 rows.  If I add '--filterAll' argument
(do not return results), then we run at 1450% of possible 1600% possible but we do 8k ops
a second.
> Let me attach flame graphs for two cases. Unfortunately, there is some frustrating dark
art going on. Let me try figure it... Filing issue in meantime to keep score in.



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