On 12 September 2011 20:02, Robin D. Wilson <rwils...@gmail.com> wrote: > Perhaps there is a workaround for this, but I have identified a small flaw > in how JMeter is running threads. > > Assume for a second that I have a test where I want to run a 100 > simultaneous users through a procedure. I'd like the test to start and > finish running 100 simultaneous threads. > > The way JMeter runs threads, it pre-divides the number of iterations among > the 100 threads - so if you are going to run 1000 loops, each thread will > get 1000 iterations to run through. > > Normally, you'd think this was OK... Since each thread will do 1000 loops, > on 'average' they will work out to do the same amount of work. > > But in practice, threads complete their 1000 loops at different intervals, > so that by the time the test completes - only a few threads were still > running at the very end. > > When you are trying to measure performance under load, this skews your > result - because the last few iterations occur with almost none of the > intended load. This means the last few threads execute very quickly compared > to threads operating while under 100 simultaneous requests - so the reported > data shows the last few threads having a significant impact on the overall > performance of the test. > > What I need is a test thread group that runs 'n' simultaneous threads from > beginning to end - and runs until 'n' _total_ iterations are complete, > instead of just 'n' per thread. Is there a thread group that works like > that?
You can set the test group to run unlimited loops, and give it a scheduled duration such that the start-up time is a small portion of the total time. Or just take the JTL data from an existing test and ignore the startup and shutdown portion in the analysis. > -- > Robin D. Wilson > Sr. Director of Web Development > KingsIsle Entertainment, Inc. > VOICE: 512-777-1861 > www.KingsIsle.com > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: jmeter-user-unsubscr...@jakarta.apache.org > For additional commands, e-mail: jmeter-user-h...@jakarta.apache.org > > --------------------------------------------------------------------- To unsubscribe, e-mail: jmeter-user-unsubscr...@jakarta.apache.org For additional commands, e-mail: jmeter-user-h...@jakarta.apache.org
