Software Testing

Performance counters and there meaning in JMeter

Common performance counters and there meaning in JMeter.

Elapsed time JMeter measures the elapsed time from just before sending the request to just after the last response has been received.  It does not include the time needed to render the response, nor does JMeter process any client code.

LatencyJMeter measures the latency from just before sending the request to just after the first response has been received. Thus the time includes all the processing needed to assemble the request as well as assembling the first part of the response, which in general will be longer than one byte.

It is not just the network latency. It is much closer to the time which is experienced by a browser.

Median is a number which divides the samples into two equal halves. Half of the samples are smaller than the median, and half are larger (Some samples may equal the median). This is a standard statistical measure. The Median is the same as the 50th Percentile.

90% Line (90 th Percentile) is the value below which 90% of the samples fall. 90% of the request have response time that is either equal to or less than “90% line response time”. This is a standard statistical measure.

Standard Deviation – is a measure of the variability of a data set. This is a standard statistical measure. JMeter calculates the population standard deviation (e.g. STDEVP function in spreadsheets), not the sample standard deviation (e.g. STDEV).

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). This is same as Hits/sec as reported by some other performance testing tools.

2 thoughts on “Performance counters and there meaning in JMeter

  1. It’s a very good article coz sometimes these parameters are misunderstood and that leads to false results…

    It would also be interesting if you could write something about….what all things one should consider while doing performance testing. Often, performance testing is mixed with load testing…’s good to measure performance of a system in such conditions but that is not all. Things like recursive calls to a same page or db, network issues, bad load sharing algos…… also degrades performance of a system.

    So, it would be great if u could write something about performance testing of a client-server based application.

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