Book Review: The Art of Application Performance Testing

The Art of Application Performance Testing, covers what it says.  The book starts with concepts general to any performance testing, which was interesting to me.  Most of the text focuses though on the Application part of the title.  The applications here are primarily web-based, or other client-server based setups, and not just the generic "application" referring to any program.  That said, I do not work on such applications, so the remainder of the text was of less value to me.

In testing applications, a performance analyst needs to establish a representative workload, which includes the actions to perform, and the combined load.  For example, most users logging in to their bank will view their account balance, while others might transfer money or pay a bill.  Combined these actions might represent most of the work from users.  Then for each unit of server, how many users should be able to perform a mix of those actions, which forms the load.

After establishing the workload, the analyst needs to implement the described workload, which requires a tool that generates the load (either by driving the application itself or replaying a synthetic trace of the load).  For those tools, what additional hardware is required to deploy this load?  Does the deployment take into account geographic and other user variations (so that the load generation is representative of the user base)?  Finally, what tooling and methodology exists for profiling and recording the execution of the workload for present and future analysis?

So I appreciated the content of the book and would recommend it to individuals focusing on testing of user-facing applications.

Repost: When Beauty is Not Truth

While it was not a field discussed in the article, When Beauty Is Not Truth, nonetheless I wonder about the focus I put on elegance in programming (starting with the name of the blog).  So let's consider a couple of quick things about Computer Science and the beauty of the code.  I should add that the article discusses a rough equivalence between beauty, elegance, and simplicity.

First, beautiful code is not always correct.

Second, beautiful code, by virtue of its simplicity, is less likely to have bugs.

Third, beautiful code is more readable, which facilitates comprehension.

(Now back to preparing the lecture for today's class)

Performance is a Feature

Performance is a Feature discusses recent performance work for the site, stackoverflow.  I found the post interesting, albeit somewhat removed from my own work due to its web focus.  As always with performance, there are two things I highlight.  First, improve the biggest contributors first.  Second, after a certain threshold, further improvements may not matter.  For example, high frequency trading depends on the microseconds required, rendering a web page does not.