Re: Sweating the small stuff: a lesson in optimisation

Very entertaining read. I hope everyone reads all the way to the end - the last benchmark cracked me up.

The only question you didn't mention was "how fast is fast enough for this application?"

If the packing/unpacking time is not a bottleneck using My_code, then you might not need the C version, removing the need for Inline::C.

Mike

Comment on Re: Sweating the small stuff: a lesson in optimisation

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Re^2: Sweating the small stuff: a lesson in optimisation by Porculus (Hermit) on Mar 16, 2009 at 21:40 UTC
That was part of the lesson, really. In practice any of the implementations would be "fast enough". The speed of this function does make a measurable difference to the run-time, but measurable isn't the same as significant; the entire program currently spends maybe two minutes a day running, so even if that was all spent in these routines, it still wouldn't make much difference. (I didn't profile before I started; I went straight to optimisation mode because this particular routine involved Other People's Code and it Looked Inefficient. Hubris again.) I wrote the final version purely out of curiosity, and it put things so firmly in perspective that I just had to write it up.	[reply]

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Re^2: Sweating the small stuff: a lesson in optimisation
by Porculus (Hermit) on Mar 16, 2009 at 21:40 UTC

That was part of the lesson, really. In practice any of the implementations would be "fast enough". The speed of this function does make a measurable difference to the run-time, but measurable isn't the same as significant; the entire program currently spends maybe two minutes a day running, so even if that was all spent in these routines, it still wouldn't make much difference.

(I didn't profile before I started; I went straight to optimisation mode because this particular routine involved Other People's Code and it Looked Inefficient. Hubris again.)

I wrote the final version purely out of curiosity, and it put things so firmly in perspective that I just had to write it up.

[reply]