Most of that is bogus. If you want, I can post some intel C++ numbers compared to gcc numbers using my suse 10.2 system (64 bit). Intel's compiler is better, but it isn't 30% better. I can also post some MSVC numbers as well, at least on my core-2 laptop.diep wrote:OS/X 64 bits has the gcc 4.0.1 inside it's notorious crappy beginners x-code compiler for os/x 10.4.9, which is the latest version currently.Tord Romstad wrote:Thanks, that sounds a lot better! Apparently my program gains about 30% when moving from 32-bit to 64-bit, so based on your numbers I can expect a total speedup of around 1.08 x 1.2 x 1.3 = 1.6848 when going from the 2 GHz Core Duo to the 2.16 GHz Core 2 Duo. Not bad.hgm wrote:This estimate is for the same (32-bit) binary. For 64-bit you get an extra acceleration, which of course strongly depends on how much 64-bit arithmetic you do compared to 32-bit stuff. For the 64-bit stuff itself it could be more than a factor 2.
Tord
That is a joke of a compiler for good chips like K8 and Core2.
There goes 30% performance...
GCC is especially bad for 64 bits code optimizations. Don't compare yourself to crafty; crafty is open source, they all managed to optimize a tad for crafty. If you're using a bit different datastructure, then 64 bits goes very bad.
In my case, some sample programs in 64 bits were 50% faster with visual c++ net2005 with pgo than latest gcc with pgo. That was tested at opteron. At core2 it's even worse.
GCC is very ugly bad there, especially if you prefer generic code rather than program out very tiny thing.
Especially try to avoid the 128 bits defines that GCC offers, a nice idea it is, but it is so so ugly bad in optimizing them.
At core2 laptops pgo from visual c++ net2005 gives diep 20+% speedup, versus 11.3% for AMD-k8. GCC again is at the wrong side there of the medal.
Vincent
p.s. about OS/X:
OS/X needs better debuggers, a better source code editor, such as multiedit is a great one for windoze, and they need to trash all their stupid mouses and keyboards, especially that 1-button mouse is a joke now that 99% of planet is used to rightbutton click a lot with mouse, besides that their 1 button mouses are causing a bunchlot of RSI problems more than normal mouses do, and resizing windows is a disaster as you need each time move your mouse to the right bottom corner instead that on every edge of the window you can resize. In GENERAL users always have their mouse a bit left in windows anyway, so resizing in the right bottom corner doesn't make sense anyway.
Also gcc 4.0.1 is just too much of a joke for such nice processors, and it is beyond any help of improvement.
And for all that you pay 30% more than PC equivalents.
Only take that macbookpro i'd say if you get it for free.
Also nobody optimizes just for my data structures. They have changed too much since the SPEC benchmark was published. I don't even use rotated bitboards any longer, so that argument is simply invalid.
