While reading EricGu’s post on Performance
of Generics, I was struck by this sentence which expresses perfectly what I was
trying to express to a group of programmers earlier today who were arguing about the
:? operators in C# being “faster” than explicit if statements. I
called B.S. on the whole topic. Thanks Eric!
Performance is rarely dominated by small decisions,
such as whether you use an ArrayList or a List<int> to store your data. It's
usually dominated by algorithmic concerns - how you process data, how much redundant
processing you're doing, etc. My experience is that the ability to be able to address
these concerns is fairly well correlated with the resiliency of your code to change,
which usually comes down to how clean and understandable the code is. If you have
clean code and good tests, it is probably feasible to refactor your code to improve
performance once you find out where the performance issues are.
Note that I'm not saying that you should put
performance off until the end - that rarely works, as time at the end is fairly precious.
I think you should focus on macro performance rather than micro performance. [EricGu]