From: Falk Hueffner <falk.hueffner@student.uni-tuebingen.de>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: dphillips@sistina.com, <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH] Faster generic_fls
Date: 30 Apr 2003 16:53:54 +0200 [thread overview]
Message-ID: <87ptn4t4sd.fsf@student.uni-tuebingen.de> (raw)
In-Reply-To: <Pine.LNX.4.44.0304300709300.7157-100000@home.transmeta.com>
Linus Torvalds <torvalds@transmeta.com> writes:
> Classic mistake. Lookup tables are only faster in benchmarks, they
> are almost always slower in real life. You only need to miss in the
> cache _once_ on the lookup to lose all the time you won on the
> previous one hundred calls.
It seems to me if you call the function so seldom the table drops out
of the cache, it is irrelevant how long it takes anyway.
> "Small and simple" is almost always better than the alternatives.
Well, if a lookup table isn't "small and simple", I don't know what
is.
--
Falk
next prev parent reply other threads:[~2003-04-30 14:42 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-30 2:46 [RFC][PATCH] Faster generic_fls Daniel Phillips
2003-04-30 7:19 ` Willy Tarreau
2003-04-30 8:36 ` Aaron Lehmann
2003-04-30 8:43 ` Aaron Lehmann
2003-04-30 8:52 ` Aaron Lehmann
2003-04-30 8:51 ` P
2003-04-30 13:51 ` Daniel Phillips
2003-04-30 11:14 ` Falk Hueffner
2003-04-30 13:03 ` Daniel Phillips
2003-04-30 13:17 ` Falk Hueffner
2003-04-30 14:07 ` Daniel Phillips
2003-04-30 14:11 ` Linus Torvalds
2003-04-30 14:53 ` Falk Hueffner [this message]
2003-04-30 15:28 ` Linus Torvalds
2003-04-30 16:03 ` Falk Hueffner
2003-04-30 16:16 ` Linus Torvalds
2003-04-30 16:43 ` Falk Hueffner
2003-04-30 20:25 ` Alan Cox
2003-04-30 21:59 ` Falk Hueffner
2003-04-30 22:22 ` Alan Cox
2003-04-30 23:41 ` Linus Torvalds
2003-04-30 22:47 ` Alan Cox
2003-05-01 0:12 ` Falk Hueffner
2003-05-01 1:07 ` Linus Torvalds
2003-04-30 19:15 ` Daniel Phillips
2003-04-30 20:59 ` Willy Tarreau
2003-05-01 1:02 ` Daniel Phillips
2003-05-01 9:19 ` Willy Tarreau
2003-05-01 16:02 ` Linus Torvalds
2003-04-30 20:55 ` Andrew Morton
2003-05-01 5:03 ` hugang
2003-05-01 5:11 ` Andrew Morton
2003-05-01 5:33 ` hugang
2003-05-01 7:05 ` hugang
2003-05-01 13:52 ` Willy TARREAU
2003-05-01 14:14 ` Falk Hueffner
2003-05-01 14:26 ` Willy TARREAU
2003-05-01 14:53 ` hugang
2003-05-01 15:54 ` Thomas Schlichter
2003-05-02 0:33 ` hugang
2003-05-01 17:16 ` Willy TARREAU
2003-05-01 23:27 ` Thomas Schlichter
2003-05-02 0:10 ` Willy Tarreau
2003-05-02 0:43 ` Daniel Phillips
2003-05-02 0:54 ` Andrew Morton
2003-05-02 12:21 ` Daniel Phillips
2003-05-02 1:47 ` Thomas Schlichter
2003-05-02 13:24 ` Willy Tarreau
2003-05-02 0:13 ` Daniel Phillips
2003-05-02 0:13 ` Lincoln Dale
2003-05-01 5:16 ` hugang
2003-05-01 10:22 ` Willy TARREAU
2003-05-01 11:17 ` hugang
2003-05-01 11:45 ` Willy TARREAU
[not found] <87d6j34jad.fsf@student.uni-tuebingen.de.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.44.0304301801210.20283-100000@home.transmeta.com.suse.lists.linux.kernel>
2003-05-01 1:46 ` Andi Kleen
2003-05-01 4:40 ` Linus Torvalds
2003-05-01 12:00 ` David S. Miller
2003-05-02 5:14 ` Linus Torvalds
2003-05-01 13:31 linux
2003-05-01 17:15 Chuck Ebbert
2003-05-02 8:50 Chuck Ebbert
2003-05-02 9:37 ` Peter Osterlund
2003-05-02 10:04 Chuck Ebbert
2003-05-02 22:55 ` David S. Miller
2003-05-03 2:21 Chuck Ebbert
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