From: Andi Kleen <andi@firstfloor.org>
To: David Miller <davem@davemloft.net>
Cc: shemminger@linux-foundation.org, rkuhn@e18.physik.tu-muenchen.de,
andi@firstfloor.org, dada1@cosmosbay.com,
jengelh@linux01.gwdg.de, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org
Subject: Re: [PATCH] tcp_cubic: faster cube root
Date: Wed, 7 Mar 2007 13:12:46 +0100 [thread overview]
Message-ID: <20070307121246.GA7728@one.firstfloor.org> (raw)
In-Reply-To: <20070306.202052.03980320.davem@davemloft.net>
On Tue, Mar 06, 2007 at 08:20:52PM -0800, David Miller wrote:
> From: Stephen Hemminger <shemminger@linux-foundation.org>
> 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 <shemminger@linux-foundation.org>
>
> 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
next prev parent reply other threads:[~2007-03-07 12:12 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-24 1:05 [RFC] div64_64 support Stephen Hemminger
2007-02-24 16:19 ` Sami Farin
2007-02-26 19:28 ` Stephen Hemminger
2007-02-26 19:39 ` David Miller
2007-02-26 20:09 ` Jan Engelhardt
2007-02-26 21:28 ` Stephen Hemminger
2007-02-27 1:20 ` H. Peter Anvin
2007-02-27 3:45 ` Segher Boessenkool
2007-02-26 22:31 ` Stephen Hemminger
2007-02-26 23:02 ` Jan Engelhardt
2007-02-26 23:44 ` Stephen Hemminger
2007-02-27 0:05 ` Jan Engelhardt
2007-02-27 0:07 ` Stephen Hemminger
2007-02-27 0:14 ` Jan Engelhardt
2007-02-27 6:21 ` Dan Williams
2007-03-03 2:31 ` Andi Kleen
2007-03-05 23:57 ` Stephen Hemminger
2007-03-06 0:25 ` David Miller
2007-03-06 13:36 ` Andi Kleen
2007-03-06 14:04 ` [RFC] div64_64 support II Andi Kleen
2007-03-06 17:43 ` Dagfinn Ilmari Mannsåker
2007-03-06 18:25 ` David Miller
2007-03-06 18:48 ` H. Peter Anvin
2007-03-06 13:34 ` [RFC] div64_64 support Andi Kleen
2007-03-06 14:19 ` Eric Dumazet
2007-03-06 14:45 ` Andi Kleen
2007-03-06 15:10 ` Roland Kuhn
2007-03-06 18:29 ` Stephen Hemminger
2007-03-06 19:48 ` Andi Kleen
2007-03-06 20:04 ` Stephen Hemminger
2007-03-06 21:53 ` Sami Farin
2007-03-06 22:24 ` Sami Farin
2007-03-07 0:00 ` Stephen Hemminger
2007-03-07 0:05 ` David Miller
2007-03-07 0:05 ` Sami Farin
2007-03-07 16:11 ` Chuck Ebbert
2007-03-07 18:32 ` Sami Farin
2007-03-08 18:23 ` asm volatile [Was: [RFC] div64_64 support] Sami Farin
2007-03-08 22:01 ` asm volatile David Miller
2007-03-06 21:58 ` [RFC] div64_64 support David Miller
2007-03-06 22:47 ` [PATCH] tcp_cubic: faster cube root Stephen Hemminger
2007-03-06 22:58 ` cube root benchmark code Stephen Hemminger
2007-03-07 6:08 ` Update to " Willy Tarreau
2007-03-08 1:07 ` [PATCH] tcp_cubic: use 32 bit math Stephen Hemminger
2007-03-08 2:55 ` David Miller
2007-03-08 3:10 ` Stephen Hemminger
2007-03-08 3:51 ` David Miller
2007-03-10 11:48 ` Willy Tarreau
2007-03-12 21:11 ` Stephen Hemminger
2007-03-13 20:50 ` Willy Tarreau
2007-03-21 18:54 ` Stephen Hemminger
2007-03-21 19:15 ` Willy Tarreau
2007-03-21 19:58 ` Stephen Hemminger
2007-03-21 20:15 ` [PATCH 1/2] div64_64 optimization Stephen Hemminger
2007-03-21 20:17 ` [PATCH 2/2] tcp: cubic optimization Stephen Hemminger
2007-03-22 19:11 ` David Miller
2007-03-22 19:11 ` [PATCH 1/2] div64_64 optimization David Miller
2007-03-08 4:16 ` [PATCH] tcp_cubic: use 32 bit math Willy Tarreau
2007-03-07 4:20 ` [PATCH] tcp_cubic: faster cube root David Miller
2007-03-07 12:12 ` Andi Kleen [this message]
2007-03-07 19:33 ` David Miller
2007-03-06 18:50 ` [RFC] div64_64 support H. Peter Anvin
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