Hi, I'm running some load testing, nothing too heavy. 10 JMeter threads, ramp up is 30. JMeter is run from the command line and the test plan has no listeners. using the -l flag, I capture the results to a CSV file.
I then load the results file into JMeter and look at hem from a Summary Listener, View Tree Listener etc. I'm a little confused by the elapsed time results. The app under test has the ability to log the time that's taken to receive the request and complete sending the response, which for an auth API call it lists as taking 114ms for example (ronded to the closest ms) I've set up tcpdump on the machine running the app (refer to as server henceforth) and the machine running JMeter (refer to as client henceforth). tcpdump on the server reports that the time between the request and response packets to be 113.83ms, while tcpdump on the client reports that the time between the request and response packets 113.96ms However for that particular HTTP request, JMeter reports that the load time (elasped time) is 174ms and that the latency is 174 ms also. How is this discrepancy explained? As I understand it, the latency is the time taken to receive the first byte of the response and since the load time and latency are the same then it indicated that the response payload was received within 1 ms. Is this correct? Or is it even possible to achieve this? The payload size for this response is 106 bytes. From the tcpdump on the client, it's clear that the response packets are available to JMeter after 113ms so I'm concerned about what's causing the increase. FWIW, the auth request sampler has an XPath Extracter Post processor, but processing time for that's not included in the load time right??. All HTTP Samplers are Java, not HTTPClient. Regards, Noel
