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| <!DOCTYPE document |
| [ |
| <!ENTITY sect-num '22'> |
| ]> |
| <document prev="hints_and_tips.html" id="$Id$"> |
| |
| <properties> |
| <title>User's Manual: Glossary</title> |
| </properties> |
| |
| <body> |
| |
| <section name="§-num;. Glossary" anchor="glossary"> |
| |
| <p> |
| <a name="Elapsed"><b>Elapsed time</b></a>. JMeter measures the elapsed time from just before sending the request to |
| just after the last response has been received. |
| JMeter does not include the time needed to render the response, nor does JMeter process any client code, for example |
| Javascript. |
| </p> |
| |
| <p> |
| <a name="Latency"><b>Latency</b></a>. JMeter 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. |
| Protocol analysers (such as Wireshark) measure the time when bytes are actually sent/received over the interface. |
| The JMeter time should be closer to that which is experienced by a |
| browser or other application client. |
| </p> |
| |
| <p> |
| <a name="Connect"><b>Connect Time</b></a>. JMeter measures the time it took to establish the connection, including SSL handshake. Note that connect time is not automatically subtracted from <a href="#Latency">latency</a>. |
| </p> |
| |
| <p> |
| <a name="Median"><b>Median</b></a> 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. |
| See, for example: <a href="http://en.wikipedia.org/wiki/Median">Median</a> entry at Wikipedia. |
| The Median is the same as the 50<sup>th</sup> Percentile |
| </p> |
| |
| <p> |
| <a name="Percentile"><b>90% Line (90<sup>th</sup> Percentile)</b></a> is the value below which 90% of the samples fall. |
| The remaining samples too at least as long as the value. |
| This is a standard statistical measure. |
| See, for example: <a href="http://en.wikipedia.org/wiki/Percentile">Percentile</a> entry at Wikipedia. |
| </p> |
| |
| <p> |
| <a name="StandardDeviation"><b>Standard Deviation</b></a> is a measure of the variability |
| of a data set. This is a standard statistical measure. |
| See, for example: <a href="http://en.wikipedia.org/wiki/Standard_deviation">Standard Deviation</a> entry at Wikipedia. |
| JMeter calculates the population standard deviation (e.g. STDEVP function in spreadheets), not the sample standard deviation (e.g. STDEV). |
| </p> |
| |
| <p> |
| <a name="ThreadName">The <b>Thread Name</b></a> as it appears in Listeners and logfiles |
| is derived from the Thread Group name and the thread within the group.<br/> |
| The name has the format |
| <code>groupName + " " + groupIndex + "-" + threadIndex</code> |
| where: |
| <ul> |
| <li>groupName - name of the Thread Group element</li> |
| <li>groupIndex - number of the Thread Group in the Test Plan, starting from 1</li> |
| <li>threadIndex - number of the thread within the Thread Group, starting from 1</li> |
| </ul> |
| A test plan with two Thread Groups each with two threads would use the names: |
| <pre> |
| Thread Group 1-1 |
| Thread Group 1-2 |
| Thread Group 2-1 |
| Thread Group 2-2 |
| </pre> |
| </p> |
| |
| <p> |
| <a name="Throughput"><b>Throughput</b></a> 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.<br/> |
| The formula is: Throughput = (number of requests) / (total time). |
| </p> |
| |
| |
| </section> |
| |
| </body> |
| </document> |