Coding Horror

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On Managed Code Performance, Again

Managed code may be fat and slow, but it fares surprisingly well in Rico's C# port of Raymond Chen's C++ Chinese/English dictionary reader:

C# versus unmanaged C++, Chinese/English dictionary reader

Sure, the C++ version eventually outperforms the managed code by a factor of 2x, but what's interesting to me-- and what this graph makes very clear-- is that the point of diminishing returns has set in well before that happens. As Rico notes:

So am I ashamed by my crushing defeat? Hardly. The managed code achieved a very good result for hardly any effort. To defeat the managed version, Raymond had to:

  • Write his own file/io stuff
  • Write his own string class
  • Write his own allocator
  • Write his own international mapping

Of course he used available lower level libraries to do this, but that's still a lot of work. Can you call what's left an STL program? I don't think so, I think he kept the std::vector class which ultimately was never a problem and he kept the find function. Pretty much everything else is gone.

So, yup, you can definitely beat the CLR. I think Raymond can make his program go even faster.

It's a pyrrhic victory once you divide the execution time by the development time of a top Microsoft C++ coder*. Now, for certain applications at the very tip of the development pyramid, this tradeoff may still make sense. But that list of apps gets shorter and shorter with every passing day.

* Raymond Chen, who has "fixed more Windows bugs than you've had hot dinners"

Written by Jeff Atwood

Indoor enthusiast. Co-founder of Stack Overflow and Discourse. Disclaimer: I have no idea what I'm talking about. Find me here: