How to Write Fast Code

I'm glad to see people talking about one of the four stages of optimization:<p>1. Do we have to optimize this? Time is never free, and opportunity cost in terms of engineering effort is usually very significant.<p>2. Can we do less work? (this article)<p>3. What's the bottleneck? CPU, FP, memory bandwidth, lock contention?<p>4. How do we squeeze out better performance? Assembly, loop unrolling, etc.<p>I usually cringe when I hear about people talking about #4, as very few of them have asked #1, #2, or #3 yet.<p>And usually, you just hear people talking about doing what the compiler's already doing (writing it in assembly? /The compiler already does that/), usually doing a pretty reasonable job at high optimization levels. They just exchange maintainability for the warm fuzzy feeling that they've been as macho as needed.

I'm personally fascinated by the notion that efficiency and transformation seem to be intertwined. Hard problems can sometimes seem simple with a slight transformation in either the problem description or the data. Even the article is suggesting that to write fast code, transform your perspective of the problem. Do less. There seems to be something fundamental here.

This is the kind of advice that points at something so obvious that you really never thought about it and feel silly once someone points it out :)

Isn't the old adage: "the fastest code is the one you never run?"

It's an unbelievably simple statement that is applicable to many different situations, not just computer related stuff.<p>For example, right now I'm detailing some design principles for a project I'm working on.<p>I realise there is a limited amount of time to be able to complete the project effectively and to make it look decent, so in the process I've come to make some hard choices.<p>I've found the trying to be creative with less is working out well so far and in the end it should pay off.

Off-topic maybe, but: "How to Write Code Fast", now can someone point me to literature for <i>that</i>? Highly appreciated!

Or split your workload up so it can be run on 200 cores in an instant. Not to advertise, but I'm not affiliated with Nvidia - <a href="http://www.nvidia.co.uk/page/tesla_deskside.html" rel="nofollow">http://www.nvidia.co.uk/page/tesla_deskside.html</a>

"no code is faster than no code" (comes from yehuda katz afair)

I get the feeling that "John" is a literary device for the alter-ego of the author.

no code is faster then no code.