[jira] [Created] (HBASE-25832) Performance improvements for StochasticLoadBalancer

["Duo Zhang (Jira)" <ji...@apache.org>]

Duo Zhang created HBASE-25832:
---------------------------------

             Summary: Performance improvements for StochasticLoadBalancer
                 Key: HBASE-25832
                 URL: https://issues.apache.org/jira/browse/HBASE-25832
             Project: HBase
          Issue Type: Improvement
          Components: Balancer, Performance
            Reporter: Duo Zhang


This is what I posted in the slack channel.

{quote}
When refactoring balancer related code for moving them out to hbase-balancer module,  I found that we will create a OffPeakHours instance in MoveCostFunction.cost every time. So I wrote a simple JMH test to test its performance.

https://github.com/Apache9/hbase-jmh-test/blob/master/src/main/java/org/apache/hadoop/hbase/master/balancer/MoveCostFunctionBenchmark.java

For the original version,  the result is
Benchmark                                            Mode  Samples    Score  Score error  Units
o.a.h.h.m.b.MoveCostFunctionBenchmark.computeCost    avgt       10  242.312        3.853  ns/op
12:06
If I initialized OffPeakHours in constructor, then the result is
Benchmark                                            Mode  Samples   Score  Score error  Units
o.a.h.h.m.b.MoveCostFunctionBenchmark.computeCost    avgt       10  81.186        0.720  ns/op
12:06
If I also eliminate the conf.getFloat in the cost method(by storing them to a field member in constructor, the result is
Benchmark                                            Mode  Samples  Score  Score error  Units
o.a.h.h.m.b.MoveCostFunctionBenchmark.computeCost    avgt       10  4.419        0.035  ns/op
12:08
I think on a large cluster, the performance for balancer is a problem, so maybe we should try to avoid creating too many objects or calling conf.getXXX in the critical path? As we will call StochasticLoadBalancer.computeCost in every step when balancing cluster...
{quote}

For large clusters, the performance of StochasticLoadBalancer will be very important, so I think we need to treat this problem seriously and try to improve.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)