FaceBook's HipHop Software Efficiency

Haiping Zhao has a great blog entry showcasing how Facebook has been able to improve the efficiency of their applications through the development of HipHop for PHP. Simply stated, HipHop transforms PHP code into optimized C++ code. According to Zhao, this technology reduced the average CPU utilization on their servers by 50%.

This showcases two things in particular:

• Software can have a major impact on system efficiency. Even relatively good solutions like PHP can still be improved.
• Metrics that look only at hardware-centric criteria often ignore the benefits of more efficient software.

This second bullet merits further elaboration. Administrators looking at CPU utilization as an approximation of total server work accomplished would erroneously assume their servers were only doing half as much work with HipHop than they were beforehand, even though they would be doing the same amount of work with better software, just doing it more efficiently.

Future posts will talk about ways to measure useful work.

--kb