Chapter 9. Performance and profiling
This chapter covers
- Measuring performance with the xUnit.Performance library
- Profiling with PerfView
- Options on Linux for performance profiling
Premature optimization is the root of all evil.
Sir C. Antony R. Hoare
This quote by Sir Tony Hoare, popularized by Donald Knuth, is perhaps the most misunderstood guidance for writing applications that perform well. Optimizations, in this context, refer to CPU cycle counting and tuning low-level operations. Programmers love to do these things, but they can often get lost in the minutiae and miss the big picture. Sir Tony wasn’t trying to tell us to forgo considering performance when designing our applications. He was warning us against getting mired down in optimizing the wrong things.
The Bing search engine has an internal plugin system. Teams build services (plugins) that receive the search query sent by the user, and they must provide a response within a certain time limit. If the service responds too slowly, the Bing infrastructure notifies the team of the performance issue and turns off the plugin. In order to provide a new feature in Bing, teams must meet the performance criteria.
Learn more about .NET performance
If you want to learn more about performance from one of the engineers that built the Bing system, seek out Ben Watson’s book, Writing High-Performance .NET Code (Ben Watson, 2014).