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From: Linus Torvalds <torvalds@transmeta.com>
To: "David S. Miller" <davem@redhat.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] Faster generic_fls
Date: Thu, 1 May 2003 22:14:25 -0700 (PDT)	[thread overview]
Message-ID: <Pine.LNX.4.44.0305012212190.5230-100000@home.transmeta.com> (raw)
In-Reply-To: <1051790452.8772.18.camel@rth.ninka.net>


On 1 May 2003, David S. Miller wrote:
> 
> This actually is false.  GCC does not know what resources the
> instruction uses, therefore it cannot perform accurate instruction
> scheduling.

Yeah, and sadly the fact that gcc-3.2.x does better instruction scheduling 
has shown itself to not actually _matter_ that much. I'm quite impressed 
by the new scheduler, but gcc-2.x seems to still generate faster code on 
too many examples.

CPU's are getting smarter, not dumber. And that implies, for example, that 
instruction scheduling matters less and less. What matters on the P4, for 
example, seems to be the _choice_ of instructions, not the scheduling of 
them.

			Linus


  reply	other threads:[~2003-05-02  5:01 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [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   ` [RFC][PATCH] Faster generic_fls Andi Kleen
2003-05-01  4:40     ` Linus Torvalds
2003-05-01 12:00       ` David S. Miller
2003-05-02  5:14         ` Linus Torvalds [this message]
2003-05-03  2:21 Chuck Ebbert
  -- strict thread matches above, loose matches on Subject: below --
2003-05-02 10:04 Chuck Ebbert
2003-05-02 22:55 ` David S. Miller
2003-05-02  8:50 Chuck Ebbert
2003-05-02  9:37 ` Peter Osterlund
2003-05-01 17:15 Chuck Ebbert
2003-05-01 13:31 linux
2003-04-30  2:46 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
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

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