Re: [RFC] frandom - fast random generator module

[Andreas Dilger]

On Oct 16, 2003  21:28 +0200, Eli Billauer wrote:
> Allow me to supply a couple facts about frandom:
> 
> * It's not a "crappy" RNG. Its RC4 origins and the fact, that it has 
> passed tests indicate the opposite. A fast RNG doesn't necessarily mean 
> a bad one. I doubt if any test will tell the difference between frandom 
> and any other good RNG. You're most welcome to try.

The "crappy RNG" being referred to is just some code we implemented to
give us somewhat unique numbers instead of sucking CPU.

> * Frandom is written completely in C. On an i686, gcc compiles the 
> critical part to 26 assembly instructions per byte, and I doubt if any 
> hand assembly would help significantly. The algorithms is clean and 
> simple, and the compiler performs well with it.

This is still more expensive than a hw RNG (which will be about 1 ins
per 4 bytes), so it would be nice to make this arch-specific if possible
(runtime and compile time).

Cheers, Andreas
--
Andreas Dilger
http://sourceforge.net/projects/ext2resize/
http://www-mddsp.enel.ucalgary.ca/People/adilger/

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