Hi Deepak,

You need to download from here 
https://ci-builds.apache.org/job/JMeter/job/JMeter-trunk/ .

JMeter 5.4.1 is the current latest version which I guess don't have the changes 
you're looking for.


Thanks,
Prateek
________________________________
From: Deepak Chaudhari <deepak.myp...@gmail.com>
Sent: 04 June 2021 16:15
To: JMeter Users List <user@jmeter.apache.org>
Subject: Re: Wrong 90th and 95th percentile values in JMeter HTML report

Is it implemented or not yet?
I downloaded JMeter 5.4.1 and added property 
"backend_metrics_percentile_estimator = R_3" in user.properties
Still same results.

[image.png]

[image.png]

On Thu, Jun 3, 2021 at 11:43 PM Felix Schumacher 
<felix.schumac...@internetallee.de<mailto:felix.schumac...@internetallee.de>> 
wrote:


Am 03.06.21 um 20:10 schrieb Deepak Chaudhari:
Thank you very much for your reply.
Will it be in user.properties?
Do we need to install the latest JMeter version to reflect the changes?

A build from trunk can be found at 
https://ci-builds.apache.org/job/JMeter/job/JMeter-trunk/

Yes, the property can be set via user.properties.

Felix

On Thu, Jun 3, 2021 at 11:14 PM Felix Schumacher 
<felix.schumac...@internetallee.de<mailto:felix.schumac...@internetallee.de>> 
wrote:

You might find
https://bz.apache.org/bugzilla/show_bug.cgi?id=65353
interesting.

With the next nightly build or build from trunk, you should be able to use the 
new property "backend_metrics_percentile_estimator" with a value of "R_3" to 
lessen the difference between both reports. But keep in mind, that the HTML 
Report use a sliding window, while the Aggregate Report does not (and will 
eventually OOM).

Felix



Am 03.06.21 um 17:46 schrieb Deepak Chaudhari:
I need to send both the reports to the client and surely the question will come 
"Why is there so much difference?"
If there is any way with which we can generate almost similar aggregate and 
HTML reports?

On Thu, Jun 3, 2021 at 9:00 PM Felix Schumacher 
<felix.schumac...@internetallee.de<mailto:felix.schumac...@internetallee.de>> 
wrote:

Without the actual data it is impossible to say, if the reports are wrong, or 
if they follow different ways to calculate a percentile.

The problem here is, that the two reports are using different algorithms to 
calculate the percentiles. We are working with discrete numbers and here a 
percentile is more like a range than a single (correct or wrong) number. Say, 
you have the values [1, 2, 4, 8, 16, 32, 64, 128, 256, 512] want to calculate a 
90% percentile. For this you take any number that splits the (sorted) list into 
two lists, where one list has all elements, that are smaller (or equal) to the 
number and one list contains all elements that are bigger than the number. For 
this example, any number between 256 and 511.99 would be a valid 90% 
percentile. (that is of course a broad description only)

The Aggregate report currently uses a memory intensive way and stores a list 
with all values and picks the smallest number, that fits the above description. 
(This memory hogging behaviour should be fixed and would lead to less accurate 
data and less OOMs or slow JMeter instances)

The HTML report gives you a value that would probably be a good 90% percentile, 
if you would have more data like the one, you already have by picking some 
value between the lower bound and the upper bound of the described range (in 
our example something between 256 and 511.999).

As your report has very few samples (21 for the biggest difference in the 
numbers), the skew between the reported percentiles can look big, but are not 
necessarily wrong.

Note, that if the numbers that both reports tell you are far apart, that is 
probably a sign of having either too few samples, or the samples (durations of 
the samples) are distributed sparsely near the  percentile ranges.

We have discussed in the past to use the same algorithm for both components, so 
that you get consistent values, but there were always other issues, that seemed 
to be more important.

Felix

Am 02.06.21 um 15:28 schrieb Deepak Chaudhari:
Hi,

I collected JTL file during a test run and using that I'm generating HTML 
report and aggregate report. When I compare aggregate and HTML reports I found 
that 90th and 95th percentile values are wrong in HTML report.
I tried to change "jmeter.reportgenerator.statistic_window" value in 
user.properties but still getting wrong values.

Aggregate report:
[image.png]

HTML report:
[image.png]

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