System performance metaphor: Traffic in Highway

Although I dislike use new noun. I found "Traffic in Highway" is a great metaphor to describe system performance when I prepared an internal talk in my company about how to identify the bottleneck"s" of system performance and how to deal with them. They are so similar:

• The performance is bounded at the worst place.
• The worst place is hard to identify when we are in it.
• The bad places might be multiple. They should be solved at the same time to see improvement.
• It is dynamic. 

Fortunately their solutions are similar too:

• Predict the reasonable throughput roughly.
• Use mature tools to visualize the whole picture and identify the bottleneck"S".
• Solve them at the same time.
• Take some time to build a real-time monitor system.

Identifying bottlenecks sometimes is not easy. However, we can do this job by using profilers. In gcc, we use callgrind and kcachegrind. In Python, we use cProfile and gprof2dot. After identifying bottlenecks, we should know how to solve them. Solutions depend on different layers, layers are: 

• requirement selection
• macro architecture
• data structures and algorithms design
• language dark corners
• operating system
• hardware

We, programmers, need "enough" knowledge to all of them and should be capable of discussing them with experts.