本章最重要的总体教训是，干净的设计和高性能是兼容的。重写 Buffer 类可将其性能提高 2 倍，同时简化其设计并将代码大小减少 20％。复杂的代码通常会很慢，因为它会执行多余或多余的工作。另一方面，如果您编写干净，简单的代码，则系统可能会足够快，因此您一开始就不必担心性能。在少数需要优化性能的情况下，关键再次是简单性：找到对性能最重要的关键路径并使它们尽可能简单。
The most important overall lesson from this chapter is that clean design and high performance are compatible. The Buffer class rewrite improved its performance by a factor of 2 while simplifying its design and reducing code size by 20%. Complicated code tends to be slow because it does extraneous or redundant work. On the other hand, if you write clean, simple code, your system will probably be fast enough that you don’t have to worry much about performance in the first place. In the few cases where you do need to optimize performance, the key is simplicity again: find the critical paths that are most important for performance and make them as simple as possible.