Thursday, November 3, 2011

Mobile Device Loading Experiment

Using eValid's ability to mimic being a mobile device, we engineered a simple demonstration of a 1,000 browser user (1,000 BU) test of a public transportation system's schedule information page, which is intended to be delivered to users of mobile devices. You're in the station and you want to know when the next train for your destination is? But you don't want it to take too long to show you the results, or you might miss your connection.

We set eValid up to imitate an iPhone, and configured the LoadTest scenario to launch successive eValid instances at 1 second intervals. The test script takes about 15 seconds to navigate to the website and download the key schedule data page. We put the playback in "repeat mode" so that, after all 1,000 BUs were launched there would be the equivalent of 1,000 users driving the mobile device.

Finally, the single data point taken from each and every repetition — some 5,587 data points in total — was the time that the actual data page took to download. Here's the chart of the results as a function ot time within the scenario:

Chart of Derived Internal Response Times (Click to See Full Image)

The payoff information here can be seen at the beginning of the chart, when the download time was pretty much independent of the applied load -- up to about 200 BUs. After that, the more users requesting that page, the longer it took, so that at the end, with 1,000 BUs asking the download time was as long as 5 minutes. It looks like someone'll be missing the bus!

Here is the link to the full solution description: Mobile Device Loading Experiment – 1,000 BUs

No comments: