I ran the Visual Studio build again, still got about the same as I got in my last email, so yea, Visual Studio is a lot better on templates then GCC is. I wonder why GCC performs so much worse...
Indeed - an open issue. Perhaps I will play with some other options (march etc.) to see if there's something I've overlooked. Well, I have to say I'm gaining more respect for the MS compiler - I last used it a very long time ago, back then it was awful!
*scratches head*
I must be missing something very obvious, but I do not see how your and OvermindDL benchmarks can support this conclusion: as far as I can tell, you two never compared the two compilers directly, what you are seeing is that on GCC the speed up of qi_parse over atoi/strtol is less than that of MSVC, but this tells nothing about the absolute performance of the two compilers on this test (i.e. you never showed any absolute times).
As you can probably guess I don't really like absolute times. It is simple enough to try and do a cross comparison in a similar manner to the way relative values are currently calculated - it will just need a bit of tweaking, I'll give that some thought.
For what we know the gcc atoi might just be faster than msvc one. And in fact a quick google search brings these two pages:
http://tinyurl.com/mqa5yl [msvc8 atoi performance is 58% of that of msvc6] http://tinyurl.com/mzyw66 [thread containing a comparison of atoi functions of different languages and compilers, in particular it seems that MSVC atoi is really 2 times slower than gcc atoi]
A slow atoi on MSVC would explain such a difference in the tests, assuming that the ability of both compilers to optimize qi_parse is about the same.
Ah, good point - mea culpa! This is where my (diminishing) ignorance of computers gets highlighted - I was under the impression that the standard library calls would be calling the same underlying things for both compilers - clearly I'm mistaken. Thanks for the comment. My code was not originally intended for benchmarking compilers / platforms - it's just getting that way! -ed ------------------------------------------------ "No more boom and bust." -- Dr. J. G. Brown, 1997