Why Std. Dev. total in Jmeter has the value of '8596.41' while all transactions are showing '0.00'?
The standard deviation for the individual sampler is 0.00 because there is only one request/data per sample. So there is no standard deviation for only one data.That's the reason all the data e.g Average, Min, Max is the same number "4038" for the first row.
Now in the 6th row, it calculates the Total value.The field Avg, Min, Max are for all the five requests. The average is calculated based upon above 5 data.Same also happened for the Standard Deviation column. The value of std.dev at the last row is the value calculated based upon the individual average value in the above five rows. The std. dev for five data 4038,10054, 12793, 26361,2002 is 8596.408939 which is ~ 8596.41.
Please refer to this link for step-by-step calculations to work out the Standard Deviation
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I have create a test plan setting no. of threads= 1 ramp-up period= 1 and loop count = 1
If i want to verify throughput value of 2nd label i am using this formula 2/5 means (no.of samples / average time) which results in 0.4 ms but the value in jmeter is showing as 4.9/min. And how are the last two rows of summary report are calculating which include labels of Test(it is my transaction controller) and Total. Please explain with formula. The image of my summary report is in the given link.
summary report
You're using the wrong formula, according to JMeter Glossary
Throughput is calculated as requests/unit of time. The time is calculated from the start of the first sample to the end of the last sample. This includes any intervals between samples, as it is supposed to represent the load on the server.
The formula is: Throughput = (number of requests) / (total time).
So you should be dividing the number of requests not by average response time, but by the whole duration of the test.
If you want to exclude some Samplers which are "not interesting" using Filter Results Tool where you can specify the label(s) of the sampler(s) you would like to get metrics for.
Filter Results Tool can be installed using JMeter Plugins Manager
I discovered, that in Aggregate Report TOTAL THROUGHPUT value depends on thread count. And if we run tests with only one thread, total throughput is calculated as 1 / Total Average (and multiplied by 1000 to convert milliseconds to seconds, see the screenshot below).
But when we set thread count to 2 or more, total throughput is calculated the unknown way, so what I want to know is which formula is used when calculating total throughput in this case (thread count > 1), because it does not seem to be an average of all requests throughput, it's also not calculated as 1 / Total Average like described in the first case. So how exactly does this work? (Screenshot for 2 threads attached below)
Thanks.
Screenshot for 1 thread used:
aggregate_1_thread.png
Screenshot for 2 threads used:
aggregate_2_threads.png
As per doc:
http://jmeter.apache.org/usermanual/component_reference.html#Aggregate_Report
Throughput - the Throughput is measured in requests per second/minute/hour. The time unit is chosen so that the displayed rate is at least 1.0. When the throughput is saved to a CSV file, it is expressed in requests/second, i.e. 30.0 requests/minute is saved as 0.5.
So result depends both on Response time and Number of threads which influences those response times.
The total number of requests is divided by the time taken to run them, see:
https://github.com/apache/jmeter/blob/trunk/src/core/org/apache/jmeter/visualizers/SamplingStatCalculator.java#L198
I am executing same test plan for two consecutive days:
First day no of Label (column A) are more than 1400
Second day no of Label are only 968 only
First day:
Second day:
I see that first day has samples 12, throughput almost zero and KB/sec 0.1
Second has better performance. Please help me understand:
What is difference between Label/Samples/Requests?
Do Number of labels depends on Throughput and Kb/sec i.e. Column K and L?
Label is basically the name of the thread group in your case. it is basically the request name that you are hitting from JMeter.
Samples are the number of times that particular request was executed.
e.g. If you have some request called login and number of samples for login are 5 it means that the login request was executed 5 times during the test.
The number of samples would vary based on the Test settings like number of users, iterations or duration of the test specified.
The number of labels = number of samples and throughput is related to each other.
Throughput = Number of Requests per second or minute and
Kb/Second = (Throughput* Average Bytes) / 1024
So the two are correlated.
I hope this helps.
Attached is the Summary Report for my tests.
Please help me understand how is the throughput value calculated by JMeter:
example the throughput of the very first line 53.1/min, how was this figure calculated by JMeter with which formula.
Also, wanted to know how are the throughput values in the subsequent test divided into mins or secs. example the 2nd line has a throughput 1.6/sec, so how does JMeter calculate this throughput values based on the time units ?
Tried many websites on the net and have got a common reply that the throughput is the number of requests per unit of time (seconds, minutes, hours) that are sent to your server during the test. But that didn't apply to the results I see in my graph the way it was explained straight forward.
Documentation defines Throughput as
requests/unit of time. The time is calculated from the start of the first sample to the end of the last sample. This includes any intervals between samples, as it is supposed to represent the load on the server.
The formula is: Throughput = (number of requests) / (total time).
So in your case you had 1 request, which took 1129ms, so
Throughput = 1 / 1129ms = 0.00088573959/ms
= 0.00088573959 * 1000/sec = 0.88573959/sec
= 0.88573959 * 60/min = 53.1443754/min, rounded to 53.1/min
For 1 request total time (or elapsed time) is the same as the time of this single operation. For requests executed multiple times, it would be equal to
Throughput = (number of requests) / (average * number of requests) = 1 / average
For instance if you take the last line in your screenshot (with 21 requests), it has an average of 695, so throughput is:
Throughput = 1 / 695ms = 0.0014388489/ms = 1.4388489/sec, rounded to 1.4/sec
In terms of units (sec/min/hour), Summary report does this:
By default it displays throughput in seconds
But if throughput in seconds < 1.0, it will convert it to minutes
If it's still < 1.0, it will convert it to hours
It rounds the value to 1 decimal digit afterwards.
This is why some values are displayed in sec, some in min, and some could be in hours. Some may even have value 0.0, which basically means that throughput was < 0.04
I have been messing with this for a while and here is what I had to do into order for my numbers to match what jmeter says
Loop through my lines in the csv file, gather the LOWEST start time for each of the labels you have, also grab the HIGHEST (timestamp + elapsed time)
Calculate the difference between those in seconds
then do number of samples / the difference
So in excel, the easiest way to do it is get the csv file and add a column for timestamp + elapsed
First sort the block by the timestamp - lowest to highest then fine the first instance of each label and grab that time
Then sort by your new column highest to lowest and grab the first time again for each label
For each label then gather both of these times in a new sheet
A would be the label
B would be the start time
C would be the endtime+elapsed time
D would then be (C-B)1000 (diff in seconds)
E would then be the number of samples for each label
F would be E/D (samples per second)
G would be F60 (samples per minute)
I need to generate the same graphs as JMeter but from my app (C, VB, etc):
Response Times Over Time
Response Times Distribution
Response Times Percentile
How can I do this? I need a calculation algorithm.
I have a CSV log-file from JMeter with following columns:
timeStamp, elapsed, label, responseCode, responseMessage, threadName, dataType, success, bytes, grpThreads, allThreads, Latency
Response Times Over Time
Divide all rows to groups by one minute. Use timeStamp for this.
Get average of elapsed from each group. It will be Y value.
Y value is a time with one minute step for each average value.
Response Times Distribution
Sort all rows by elapsed field.
Count rows with value of elapsed field between 0 and 100. The count will be value of first column of chart.
A count of rows with value of elapsed field between 100 and 200 will be a value of chart's second column, etc.
Response Times Percentile
X - numbers from 0 to 100.
Y - according percentile value for elapsed fields.
I believe you can specify a file from which to read inside the Response Times Over Time Listener (and the others as well). Copy your results to another file and try a test with only listeners, pulling from that file.