On: “Clean Code, Horrible Performance” Discussion

[fwlr]

No, Casey’s argument is that clean code is not good for performance. The counter-argument to Casey’s argument is that when performance matters, don’t write clean. My counter-counter-argument to the counter-argument to Casey’s argument is that performance is clearly missing even when it matters, so clearly developers aren’t able to figure out when performance matters, so the counter-argument won’t work.

Bob is saying:

  doCleanCode()
  // doUglyFastCode()

Casey wants to swap that around because it’s bad for performance:

  // doCleanCode()
  doUglyFastCode()

Responses say “fine, don’t do clean code when performance matters”:

  if (performanceMatters()) { 
    // doCleanCode()
    doUglyFastCode()
  }
  else {
    doCleanCode()
    // doUglyFastCode()
  }

I’m saying “most developers implementation of `performanceMatters` is bugged, it always returns false”. My evidence is that “here, look at all these cases where `performanceMatters` should return true and yet we’re obviously getting the results of the else clause”.

You’re objecting that I don’t know the bad performance in a given case is because of a `doCleanCode` call, I haven’t looked at the source, it could very well be for other reasons:

  if(performanceMatters()) {
    doDirectDrawToScreen()
  }
  else {
    doDispatchDebouncedStateChangeToUserInterfaceFramework()
  }

Can you see how that doesn’t detract from my argument? We’re obviously never getting to the `performanceMatters() == true` branch of the conditional, so putting Casey’s suggestion in that branch of the conditional means we never do it. It does not matter if my evidence for “we never get to the `performanceMatters` branch” comes from statements that include `doCleanCode` or not.

[lazyasciiart → fwlr]

So you are saying not that “here they chose Clean Code” but “here they chose not to make good performance”. You’re arguing that the only reason for poor performance is that the developers didn’t think it mattered?

[fwlr → lazyasciiart]

Sort of? I completely agree with Casey’s argument that Clean Code makes for poor performance, but I’m not making that argument here, he’s made it for me. I am arguing that many developers are really bad at knowing when performance matters, so if they implement the advice of “write clean code, except when performance matters” they are never going to think performance matters and always write clean code. Does that help?