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What is 95% percentile Messages in this topic - RSS

Unregistered User
Unregistered User
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2/22/2018
Unregistered User
Unregistered User
Posts: 188
I have a question related to 95% response time data in transaction detail. As per the documentation, 95% is the maximum response time after excluding the slowest 5% of transaction iterations. In the following graph, there are 20 iterations and the data given by the tool is

Avg - 0.577
Min - 0.406
Median -0.406
90% - 0.844
95% - 2.923
Max - 2.923

95% and Max are the same. But if we go by the documentation 95% should exclude the slowest 5% transaction. 5% of 20 is 1. Shouldn't 95% exclude 2.93?

Please help me understand.


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George @StresStimulus
George @StresStimulus
Administrator
Posts: 117


2/22/2018
George @StresStimulus
George @StresStimulus
Administrator
Posts: 117
“95%” percentile deals with a sequence of transaction times measured for all users and iterations. To determine this information, the followings two steps are performed:
  • Out of all of your Transaction times exclude 5% of the slowest responses.
  • Then take the slowest of the remaining responses. This will be the “95%” percentile.

  • This information is available in a waterfall graph, where you can request the transaction durations for any VU and iteration.


    The graph that you provided, on the other hand, shows the minimum transaction time reported between the data points. For example, if your sample rate is set to 5 minutes, then your measurement of 2.93 can mean that, if during the first 5 minutes of the test let’s say 50 out of 300 VUs completed this transaction, then the slowest of these transaction times was 2.93. As you can see, the graph measurements cannot be directly converted to percentiles on the report. This graph merely indicates how transaction times change as the test was progressing.
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    Unregistered User
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    2/22/2018
    Unregistered User
    Unregistered User
    Posts: 188
    Thanks for explanation.

    So you mean 95% value is the maximum response time of those 5% slowest responses?
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    George @StresStimulus
    George @StresStimulus
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    Posts: 117


    2/22/2018
    George @StresStimulus
    George @StresStimulus
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    Posts: 117
    The 95% value is the minimum response time of the slowest 5%of responses.

    What you are asking (the maximum response time of the slowest 5%of responses) is the slowest response.
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    Unregistered User
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    2/23/2018
    Unregistered User
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    Ok, so can I say that 95% means 95% of the transactions were at or under this response time?
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    George @StresStimulus
    George @StresStimulus
    Administrator
    Posts: 117


    2/23/2018
    George @StresStimulus
    George @StresStimulus
    Administrator
    Posts: 117
    Correct, 95% of the transaction times were faster than 2.92 seconds.
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