[
https://issues.apache.org/jira/browse/AVRO-2269?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16689325#comment-16689325
]
ASF GitHub Bot commented on AVRO-2269:
--------------------------------------
rstata commented on issue #384: AVRO-2269 A few changes to lower the runtime
variance of Perf.java tests
URL: https://github.com/apache/avro/pull/384#issuecomment-439372811
I'm closing this pull request for now while I look at some performance
results more carefully.
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
> Improve variances seen across Perf.java runs
> --------------------------------------------
>
> Key: AVRO-2269
> URL: https://issues.apache.org/jira/browse/AVRO-2269
> Project: Apache Avro
> Issue Type: Test
> Components: java
> Reporter: Raymie Stata
> Assignee: Raymie Stata
> Priority: Major
>
> In attempting to use Perf.java to show that proposed performance changes
> actually improved performance, different runs of Perf.java using the exact
> same code base resulted variances of 5% or greater – and often 10% or greater
> – for about half the test cases. With variance this high within a code base,
> it's impossible to tell if a proposed "improved" code base indeed improves
> performance. I will post to the wiki and elsewhere some documents and scripts
> I developed to reduce this variance. This JIRA is for changes to Perf.java
> that reduce the variance. Specifically:
> * Access the {{reader}} and {{writer}} instance variables directly in the
> inner-loop for {{SpecificTest}}, as well as switched to a "reuse" object for
> reading records, rather than constructing fresh objects for each read. Both
> helped to significantly reduce variance for
> {{FooBarSpecificRecordTestWrite}}, a major target of recent
> performance-improvement efforts.
> * Switched to {{DirectBinaryEncoder}} instead of {{BufferedBinaryEncoder}}
> for write tests. Although this slowed writer-tests a bit, it reduced variance
> a lot, especially for performance tests of primitives like booleans, making
> it a better choice for measuring the performance-impact of code changes.
> * Started the timer of a test after the encoder/decoder for the test is
> constructed, rather than before. Helps a little.
> * Added the ability to output the _minimum_ runtime of a test case across
> multiple cycles (vs the total runtime across all cycles). This was inspired
> by JVMSpec, which used to use a minimum. I was able to reduce the variance
> of total runtime enough to obviate the need for this metric, but since it's
> helpful diagnostically, I left it in.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
