Subject: Re: [PATCH] tcp_cubic: faster cube root

From: Andi Kleen <[email-masked]>
Date: Wed, 7 Mar 2007 13:12:46 +0100

On Tue, Mar 06, 2007 at 08:20:52PM -0800, David Miller wrote:
> From: Stephen Hemminger <[email-masked]>
> Date: Tue, 6 Mar 2007 14:47:06 -0800
> 
> > The Newton-Raphson method is quadratically convergent so
> > only a small fixed number of steps are necessary.
> > Therefore it is faster to unroll the loop. Since div64_64 is no longer
> > inline it won't cause code explosion.
> > 
> > Also fixes a bug that can occur if x^2 was bigger than 32 bits.
> > 
> > Signed-off-by: Stephen Hemminger <[email-masked]>
> 
> Applied, thanks Stephen.

Well that still needs the ugly div64_64 function. At least my goal was to 
eliminate that, not make it faster (I don't see any evidence this function 
is particularly performance critical). You prefer to keep div64_64? 

-Andi