From: Francis Cianfrocca <garbagecat10@...>
Date: 2006-07-27T05:15:56+09:00
Subject: Re: For performance, write it in C

Ron M wrote:
 > Not really.  In C you can quite easily use inline assembly
> to do use your chips MMX/SSE/VIS/AltiVec extensions and if
> you need more, interface to your GPU if you want to use it
> as a coprocessor.
> 
> I don't know of any good way of doing those in Java except
> by writing native extensions in C or directly with an assembler.
> 
> Last I played with Java it didn't have a working cross-platform
> mmap, and if that's still true, the awesome NArray+mmap Ruby
> floating around is a good real-world example of this flexibility.


Your point about Java here is very well-taken. I'd add that you don't 
even really need to drop into asm to get most of the benefits you're 
talking about. C compilers are really very good at optimizing, and I 
think you'll get nearly all of the available performance benefits from 
well-written C alone. (I've written at least a million lines of 
production asm code in my life, as well as a pile of commercial 
compilers for various languages.) It goes back to economics again. A 
very few applications will gain so much incremental value from the extra 
5-10% performance boost that you get from hand-tuned asm, that it's 
worth the vastly higher cost (development, maintenance, and loss of 
portability) of doing the asm. A tiny number of pretty unusual apps 
(graphics processing, perhaps) will get a lot more than 10% from asm.

The performance increment in going from Ruby to C is in *many* cases a 
lot more than 10%, in fact it can easily be 10,000%.

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