The Web Performance load engine is the software Load Tester uses to create virtual users and generate load on the target. As with Load Tester, the load engine is a Java-based application that runs on its own Java virtual machine, which is included in the installation. There are two places the load engine is used: the local engine, which is included with Load Tester and runs inside the Load Tester JVM; and the remote engine, which is a standalone installation with its own JVM. The local engine is limited and intended mainly for replays and small tests, so in this … Continue reading »
Is your load balanced website using more bandwidth under load than a single server would? In a previous article (“Status code 200 didn’t match expected: 304”), we discussed how a website may return full data content back to a client, even when the browser had the resource cached. If you believed that adding an extra server and a load balancer will increase your performance, this can be an unsettling surprise. The problem arises when two web servers are delivering different Entity Tags for the same static resource:
In this example, we have two requests made to the same public URL, … Continue reading »
We know we’ve got great people working here…but we still love it when a customer takes time out of their busy days to compliment one of them. After some recent on-site training and performance tuning for a local customer, George Terrone, President of Integrated Technical Services, wrote to tell us this:
Matt did an absolutely fantastic job. And the timing of his engagement could not have been better. He not only helped our customer understand your product better – he helped to solve a serious Apache problem that had stymied us all.
His Apache expertise – and his attitude – were both … Continue reading »
I’m in Orland this week attending the 2010 StarEast conference for software testing, and was surprised at how much hadn’t changed. Its been over a decade since my last tech conference, and while the names have changed, the actual recommended practices haven’t changed much at all. Speakers are still preaching the values of early testing, automated test suites, and automated build processes that I learned as a young engineer at Sun Microsystems 20 years ago, but now they’re called “agile” and “ATDD“.
The only controversial statement of the day was in Jeff Payne’s opening keynote, where … Continue reading »
When Bell Canada began development of an important new customer-facing application, project lead Mr. Roger Bejjani knew he needed to find a web testing tool that would help fine-tune performance throughout the development process and into production. Having used Empirix (purchased by Oracle) and Load Runner (purchased by HP)in the past, he decided to forgo overpriced software and look for a tool that would give him the functionality he needed at a more reasonable price. The main requirement would be load testing HTTP and HTTPS requests, and the software needed to be easy to use during development as well as … Continue reading »
Need to generate thousands of concurrent users but don’t want to pay big bucks for a large license? You may not know that licenses to generate 1,000 or more concurrent users are available on a week-by-week basis. And now that Load Tester 4 can automatically generate massive amounts of load against data centers, leasing makes even more sense.
For existing customers, this means they can purchase a lower-level license for day-to-day use, and then just lease the larger licenses for a big final round of testing. We’ve had a tremendous response from existing customers who normally test with just a … Continue reading »
I ran across this article yesterday. It is nearly two years old, but the content is still entirely relevant. If you are building a system that needs to scale out to handle a large load, then you’ve probably already read this or something similar…if not, then it is worth your time.
What is the relevance to Load Testing, you ask? In section 5 author, Simon Brown, says”
“… set measurable goals throughout the system, verify and measure the real performance and consider performance at all stages of the project.”
For a project manager, a key part of the job is reducing risk … Continue reading »
From a load testing perspective, we are not generally concerned with Javascript performance – since it affects client-side rendering time and therefore has little relationship to load. However, we do see a lot of sites that could benefit greatly from improved Javascript performance – especially reducing the size of their Javascript files. Google has a relatively new project, Closure Compiler, that optimizes JavaScript code to reduce size and improve performance.
If you’ve tried the Closure Compiler, give us a shout. We’d love to hear about your results!
Chris
Chief Engineer
In part 1 of How User Ramping Works, we discussed how to set up a user ramp configuration for a test. When you’ve done that, recorded and replayed your test cases to perfection, loaded your datasets, configured your load engines, and set up your server agents, what actually happens when you push the big green button?
The first thing Load Tester does is go through a setup sequence that configures the load engines for the coming test. This can take a while, especially if you’ve configured large datasets or large numbers of files to be … Continue reading »
I ran across these slides that present an introduction to load testing for developers. Being primarily a developer myself, I thought it might be worth a read. It is pretty light – it would be nice to get a video with the entire presentation. But it does raise some good points that many developers can benefit from. I particularly liked that the author (Simon Brown) differentiated between performance and scalability – a difference that is easy to miss. He also points out that you cannot predict system performance, either from diagrams and charts or by extrapolating results from past … Continue reading »