Am 15.05.19 um 17:28 schrieb Philippe Mouawad: > Hello, > > I'll start with my team the development of a switch to better percentiles > computation which will end as a PR contribution. > > To recap previous discussions: > > - We have currently 2 implementations of Percentiles : > - A custom one used in old listeners > - A new one based on commons-math > - CONS: > - It impacts maintainability as a consequence > - The results are different which confuses users > - Percentiles are not explicitly documented regarding the algorithm > used which also creates confusion : > - https://github.com/apache/jmeter/pull/295 > - https://github.com/apache/jmeter/pull/296 > - Benefits: > - Have one algorithm in codebase > - Rely on best percentile algo for our use case > - Rely on performing and reliable library HdrHistogram/LatencyUtils > - Improve CO handling > - PREVIOUS ACTIONS: > - It was agreed that switching to HdrHistogram was a good option. This > library is a standard now: > - Used in MicroMeter (used by Spring) > - Used in future JMC > https://mail.openjdk.java.net/pipermail/jmc-dev/2019-May/000984.html > - Felix started a PR: > - https://github.com/apache/jmeter/pull/380/files
I updated the branch and thus the PR to be hopefully more correct than the old one. I still have a few doubts about the implementation. It seems to me, that HdrHistogram is good for collecting the stats, but not optimized for asking the stats a lot while the test is running. That is the reason, that I tried to implement the calculation of some of those stats myself. There is a good change, that I completely messed it up. > - Vladimir mentioned LatencyUtils in this PR: > - Used in MicroMeter > - Based on Gil Tene work who is master of CO related issues as > long as other titles > > > *PROPOSED ACTION PLAN:* > > - We'll start our work using LatencyUtils which seems interesting as it > provides a PauseDetector which will be useful in our case > > > If you have any note on this, feel free to add your ideas in this thread. Have a look at the performance of the reports while the stats are collected. Felix > > Regards > Philippe M. > UbikLoadPack Team > > > > > > > <https://www.openstreetmap.org/#map=18/50.69454/3.16455> >
