CustomerCentrix

There are several good posts about why people should tune their apps. Lots of other good places to find info on HOW to tune.

Web performance tuning does a great job of using case studies and research by the big companies to prove the correlation between web performance and profit. It's obvious - slow pages make users go away; thus, revenue is lost.

Top Ten Web Performance Tuning Tips
by Patrick Killelea, author of Web Performance Tuning is a good read for ideas. Patrick rightly points out that too many times performance testing is overlooked.

Load test fundamentals usually only talk about the technical aspects, but this post lists several outstanding questions that should be asked up front to understand the who, what, when, why, and how of load testing.

Load tests are difficult to get just right because there are so many variables. But if you don't clearly define the measurements of success before you start, then I guarantee that some manager somewhere is going to be mad. And of course, blame rolls down hill.

So begin your load testing process with getting the right context.

On May 26, Alois Reitbauer wrote a post about Is There a Business Case for Application Performance? Alois quotes some interesting statistics from a dynaTrace study that show performance management is not a high priority in most companies.

• 6o percent of the companies admit that they do not have any performance management processes installed or what they have is ineffective.

• Half of the companies who answered that they have performance management processes admitted that they are doing it only in a reactive way when problems occur.
  

In life, I've found that much of failed communication is due to the misunderstand of what someone means when they use a particular word or phrase. Bill Clinton exemplified this fact when he asked his impeachment questioners to define "is". Oh boy.

Many application developers use the term performance testing to mean different things. So here are some great sources for defining what is meant by performance testing in the context of software applications.

performance testing definitions

wikipedia defines performance testing

There are many good articles out there about performance testing. Here are a few to get you started.

PerfTestPlus - Scott Barber, well-known performance testing author

Performance Testing Articles on Performance-testing.org is a good list

Meeting performance testing goals before moving an application into production

I did a Google search on "performance testing statistics" and was disappointed by what I found. It seems that most of the results are about tools gathering data during the test. I was hoping to find out more about how the industry of load and performance testing compiles information on a macro level.

Here is the best source I found on performance testing statistics that relate to how companies use application performance management. Especially useful are the statistics around how performance affect customers and impact revenue.

There can be unique performance issues introduced when running your application across multiple company networks or in different vendor clouds. Some architects decide to address dispersed user populations by putting a copy of the app in their geography. For instance, LoadStorm runs in Virginia, California, Singapore, and Ireland in order to provide testing that has user traffic originating on different continents.

Any complex data center or network environment can blow up your performance testing models if you don't account for them in test planning and execution. You can get the proper steps built into your scenarios such that the relative volume of user types (anonymous, buyers, admins, etc.) are represented. That said, you probably want to test the scenario volume coming from a corresponding geo.

Application lifecycle performance testing and monitoring strategies on SearchSoftwareQuality by Mike Kelly is an interesting read that has some good info about load and performance testing.

Selected quotes:

"Application performance is often a series of tradeoffs that occur throughout the application lifecycle."

"If we allow for emergent design, we may not recognize the need for a focus on low-level performance metrics early in the project"

"This is why application performance testing and monitoring can be so important for some projects. As teams work to test pre-production, and monitor post-production, they are often looking to tune their application to an ever-changing operating environment with an evolving user population. Tuning application performance isn't unlike sound-mixing – where you're asking people with some specialized skills to "listen" to your application and move a bunch of knobs, sliders, and dials to obtain optimal performance."

ALM has always been one of those acronyms I hear and immediately tune out. In banking, it means Asset Liability Management. In programming world, it stands for Application Lifecycle Management. So what does that mean?

Matt Heusser offers a good description in his article posted on March 1, 2010 on SearchSoftwareQuality.com:

For our purposes, let's call ALM "Any tools, technologies, or techniques that attempt to connect and maintain connections between activities over the life of a piece of software – from the first glint in the glimmer of an executive's eye, through system retirement." Notice I said attempt. It turns out that many of the important facts about a software project are never written down, and that even those that are can be misinterpreted and misunderstood. The typical project is actually a collection of ideas held in the minds of the people on the project; compressing that into relevant bits of unambiguous code will work, but English is interpreted.

David Johnson wrote a good article back in December entitled Building a Performance Assurance Center of Excellence tutorial. In it, David makes a solid high-level case for why performance testing is important.

Here is the excerpt:

Unfortunately, users usually remember the worst experience with a company better than the best experience. So, performance testing is a crucial component of any deployment because application performance has a direct impact on the end-user experience, which directly impacts your revenue stream. Performance testing can make the difference between a satisfied customer and a customer who switches to a competing provider.