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https://issues.apache.org/jira/browse/FLINK-29825?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17682413#comment-17682413
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Yanfei Lei commented on FLINK-29825:
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Sorry for the late reply, I'm planning to improve the stability regression
detection script.
Leveraging [Two sample Kolmogorov-Smirnov
test|https://en.wikipedia.org/wiki/Kolmogorov%E2%80%93Smirnov_test#Two-sample_Kolmogorov%E2%80%93Smirnov_test]
to detect regression is a good idea:
(1) I‘m concerned it's not easy to construct the first distribution: "all
latest samples, from the latest one (1st one), until N'th latest sample". If
some regressions have occurred before, it will "distort" the first
distribution, possibly leading to false positive; meanwhile, optimization can
also cause "distortion" which possibly leads to false negative, It's relatively
acceptable. Maybe we can filter out outliers to avoid this problem.
(2) Also, [Kolmogorov-Smirnov
test|https://en.wikipedia.org/wiki/Kolmogorov%E2%80%93Smirnov_test#Two-sample_Kolmogorov%E2%80%93Smirnov_test]
is an absolute value, and it is impossible to identify whether it is an
improvement or a regression.
My plan is/was to use the error to adjust each threshold, each benchmark run
has an error value in the result,
let thr=0.75*(max error of N'th latest sample), and the other logic is the same
as the existing detection script.
> Improve benchmark stability
> ---------------------------
>
> Key: FLINK-29825
> URL: https://issues.apache.org/jira/browse/FLINK-29825
> Project: Flink
> Issue Type: Improvement
> Components: Benchmarks
> Affects Versions: 1.17.0
> Reporter: Yanfei Lei
> Assignee: Yanfei Lei
> Priority: Minor
>
> Currently, regressions are detected by a simple script which may have false
> positives and false negatives, especially for benchmarks with small absolute
> values, small value changes would cause large percentage changes. see
> [here|https://github.com/apache/flink-benchmarks/blob/master/regression_report.py#L132-L136]
> for details.
> And all benchmarks are executed on one physical machine, it might happen that
> hardware issues affect performance, like "[FLINK-18614] Performance
> regression 2020.07.13".
>
> This ticket aims to improve the precision and recall of the regression-check
> script.
>
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