I'm having some trouble getting the Constant Throughput Timer to work the way I want in certain cases.
I have a single thread group of 100 threads, all of which are requesting the same resource over and over for 1 minute. I attached a Constant Throughput Timer on the thread group and ran a series tests with the throughput throttled at higher and higher levels such as 6000, 8000, 10000, etc. Here is a table showing the throughput timer settings and the actual number of requests that the server under test responded to: thruput-setting..........actual-requests-served 36,000.....................36,000 48,000.....................48,000 60,000.....................60,000 72,000.....................60,000 84,000.....................60,000 So it looks like the server under test simply can't respond to more than 60,000 requests per minute right? However, when I disable the throughput timer I get way higher throughput, something like 350,000 requests per minute. What's going on here? Why is the throughput timer giving me these results? Is it possible that JMeter is spending so much time trying to keep the throughput at the right level that it doesn't have enough cycles left to dedicate to actual requests? I tried distributing the load across multiple load generators but it didn't seem to help. The results above have the throughput timer configured using Calculate Throughput based on = "all active threads in current thread group". I tried changing this to "all active threads in current thread group (shared)" and I get the maximum results of 350,000 as if the throughput timer was not even there. I must admit I don't understand the difference between the two settings, but neither result sounds right. Any ideas about this?
