Introduction:
"Computers are useless. They can only give you answers." Pablo Picasso
(18811973)
Performance testing is the discipline concerned with determining and reporting the
current performance of a software application under various parameters. My series
"User Experience, Not Metrics" discusses and demonstrates how to do it, with the
help of the Rational Suite짰 Test Studio짰 system testing tool.


Part 2: A Performance Engineering Strategy
Without a strategy, performance engineering is simply an exercise in trial and
error. Following a sound strategy in the engineering effort will increase your
performance engineering team셲 efficiency and effectiveness. This article
outlines a strategy that complements the Rational Unified Process짰 approach
and is easily customizable to your project and organization, and that셲 been
validated by numerous clients worldwide. The templates I provide will give you
a starting point for documenting your performance engineering engagement.
Applying this strategy, coupled with your own experience, should significantly
improve your overall effectiveness as a performance engineer.

Part 3: How Fast is Fast Enough?
"You thought that was fast? I thought it was fast. Well, was it?"
Jodie Foster as Annabelle in the movie Maverick (1994)
(This item originally appeared on The Rational Developer Network, an online
community for customers of IBM Rational Software. To find out more,
including how you can get a free evaluation to the Rational Developer
Network, please visit http://www.rational.com/services/rdn/find_out_more.jsp)
As a moderator of performance-related forums on QAForums.com, I셶e seen
questions like this one posed numerous times:
"I셫 desperately trying to find out what the industry standard response times are.
What are reasonable benchmarks that are acceptable for Web sites at the moment?
Is 1.5 seconds a reasonable target????"
My answer to questions like this one always starts with "It depends on . . . " My friend
Joe Strazzere addressed this question particularly well, as follows:
There are no industry standards.

Part 4: Accounting for User Abandonment

(This article has been adapted from the made for Rational Developers Network
article series 쏝eyond Performance Testing.
Have you ever gotten tired of waiting for a Web page to load and exited the
site before completing the task you had in mind? No doubt you have, just like
every other Web user. Although user abandonment is a routine occurrence, it
isn셳 commonly discussed in the context of developing and analyzing
performance tests.
Here in the fourth article of the 쏝eyond Performance Testing series, we셪l explore
performance-testing issues related to user abandonment and how to account for
these issues using the Rational Suite짰 TestStudio짰 system testing tool.

Part 5: Determining the Root Cause of Script Failures

In the forums on performance engineering that I participate in and moderate, I
get questions like these almost daily:
쏧 recorded my script and it worked just fine for one user, but when I tried
two users they both failed. What셲 wrong with my Web server?
쏮y scripts pass but the database doesn셳 get updated. What셲 wrong with
my database?
쏮y scripts work for five users, but when I play back more than ten users
my scripts time out. Is my application overloaded already?!

Part 6: Interpreting Scatter Charts
쏷he purpose of analytical displays of information is to assist
thinking about evidence.
Edward Tufte, PhD (2003)
Scatter charts are by far the single most powerful visual evaluation tool at a
performance engineer셲 disposal. Wise use of this simple-seeming type of
chart will greatly shorten your search for those often-elusive bottlenecks.


Share