A detailed discussion of this issue can be found in here https://dzone.com/articles/how-to-achieve-better-accuracy-in-latency-percenti
On Wed, Nov 29, 2017 at 5:43 AM, Malith Jayasinghe < [email protected]> wrote: > .Hi Phiilppe, > > No, I did not create this issue. There is a significant increase in the > accuracy when using "large" window sizes. > > Thanks > > Malith > > > On Wed, Nov 29, 2017 at 3:53 AM, Philippe Mouawad < > [email protected]> wrote: > >> Hello, >> Any feedback on this ? >> Are you the opener of this ?: >> >> - https://bz.apache.org/bugzilla/show_bug.cgi?id=61725 >> >> Thanks >> >> On Thu, Nov 23, 2017 at 11:32 PM, Philippe Mouawad < >> [email protected]> wrote: >> >> > Hello, >> > You can adjust accuracy by setting in user.properties: >> > >> > - jmeter.reportgenerator.statistic_window = 20000 >> > >> > Caution : higher value provides a better accuracy but needs more memory. >> > >> > This is not a bug. >> > >> > We use DescriptiveStatistics from commons-math with a sliding window. >> > >> > So if after modifying this value you still face issue, please report and >> > open a bug at commons-math. >> > >> > Regards >> > >> > >> > On Thu, Nov 23, 2017 at 5:04 AM, Malith Jayasinghe < >> > [email protected]> wrote: >> > >> >> Dear All, >> >> >> >> We have been using JMETER extensively for performance testing. >> >> >> >> All our performance reports are generated using the JMETER Dashboard. >> >> >> >> Recently, we have found out that there is an issue in >> >> the JMETER dashboard's *latency percentile calculation. * >> >> >> >> There is a significant difference in the actual percentile values and >> the >> >> values shown in the dashboard. We have verified this using "R" and in >> >> fact, >> >> the values shown the JMETER aggregate report are correct. The values >> that >> >> appear in the JMETER Dashboard are not. >> >> >> >> We understand that JMETER Dashboard may be using a different algorithm >> >> (approximation) for percentile calculation. However, the problem is >> that >> >> that latency percentiles values calculated using this algorithm are not >> >> accurate (at least for certain scenarios). >> >> >> >> We have had a case where the Dashboard showing a 95% percentile value >> 1000 >> >> ms. However, the correct value was 321 ms. >> >> >> >> The accuracy of percentile values are of utmost importance to us and we >> >> would kindly ask you to look into this issue and release a patch if >> >> possible. >> >> >> >> If you can implement the same algorithm used in the aggregate report >> >> within >> >> the dashboard that will resolve this issue. >> >> >> >> >> >> Thanks >> >> >> >> Malith Jayasinghe >> >> >> > >> > >> > >> > -- >> > Cordialement. >> > Philippe Mouawad. >> > >> > >> > >> >> >> -- >> Cordialement. >> Philippe Mouawad. >> > >
