Messages in this thread | | | Date | Wed, 07 Mar 2007 19:10:47 -0800 | From | Stephen Hemminger <> | Subject | Re: [PATCH] tcp_cubic: use 32 bit math |
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David Miller wrote: > From: Stephen Hemminger <shemminger@linux-foundation.org> > Date: Wed, 7 Mar 2007 17:07:31 -0800 > > >> The basic calculation has to be done in 32 bits to avoid >> doing 64 bit divide by 3. The value x is only 22bits max >> so only need full 64 bits only for x^2. >> >> Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> >> > > Applied, thanks Stephen. > > What about Willy Tarreau's supposedly even faster variant? > Or does this incorporate that set of improvements? > That's what this is: x = (2 * x + (uint32_t)div64_64(a, (uint64_t)x*(uint64_t)x)) / 3;
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