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From: "H. Peter Anvin" <hpa@zytor.com>
To: Gerd Knorr <kraxel@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, Andi Kleen <ak@suse.de>,
	Linus Torvalds <torvalds@osdl.org>, Dave Jones <davej@redhat.com>,
	Zachary Amsden <zach@vmware.com>, Pavel Machek <pavel@ucw.cz>,
	Andrew Morton <akpm@osdl.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Zwane Mwaikambo <zwane@arm.linux.org.uk>,
	Pratap Subrahmanyam <pratap@vmware.com>,
	Christopher Li <chrisl@vmware.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Ingo Molnar <mingo@elte.hu>
Subject: Re: [patch] SMP alternatives
Date: Wed, 23 Nov 2005 08:51:40 -0800	[thread overview]
Message-ID: <43849E1C.3030102@zytor.com> (raw)
In-Reply-To: <43849C23.3040001@suse.de>

Gerd Knorr wrote:
> 
> Patching in/out SMP-locking with more than one active CPU would be a 
> pretty silly idea in the first place ;)
> 

No, doing this crap with CPU hotplug is a silly idea.  Patching on a 
real UP system, and then throwing out the tables, makes sense.  Keeping 
two sets of tables for a minimal performance improvement in a very rare 
configuration (CPU hotplug is the exception, not the rule) is just plain 
stupid.  You probably lose as much performance from the memory hogged up 
in the tables as you gain from it, and on every system where you have 
the tables at all you take the hit.

	-hpa

  reply	other threads:[~2005-11-23 16:52 UTC|newest]

Thread overview: 163+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-11-10  0:32 [PATCH 1/10] Cr4 is valid on some 486s Zachary Amsden
2005-11-11 10:36 ` Pavel Machek
2005-11-11 17:49   ` H. Peter Anvin
2005-11-11 18:00     ` Maciej W. Rozycki
2005-11-11 19:36   ` Zachary Amsden
2005-11-11 19:58     ` Linus Torvalds
2005-11-11 20:14       ` Zachary Amsden
2005-11-11 20:22         ` Linus Torvalds
2005-11-13  7:42           ` Dave Jones
2005-11-13 10:59             ` Andi Kleen
2005-11-13 17:26               ` Alan Cox
2005-11-13 17:09                 ` Eric W. Biederman
2005-11-13 19:00                 ` Andi Kleen
2005-11-13 19:07                   ` Eric W. Biederman
2005-11-13 19:41                   ` Alan Cox
2005-11-13 19:36                     ` Linus Torvalds
2005-11-13 21:32                       ` Alan Cox
2005-11-14  7:46                         ` Arjan van de Ven
2005-11-13 19:56                 ` H. Peter Anvin
2005-11-13 19:24             ` Linus Torvalds
2005-11-13 20:29               ` Linus Torvalds
2005-11-14 15:06                 ` Gerd Knorr
2005-11-14 19:25                   ` Linus Torvalds
2005-11-14 19:46                     ` Zachary Amsden
2005-11-14 19:52                       ` Arjan van de Ven
2005-11-14 20:34                         ` Zachary Amsden
2005-11-14 20:52                           ` Arjan van de Ven
2005-11-15 14:12                     ` Gerd Knorr
2005-11-15 16:01                       ` Gerd Knorr
2005-11-15 16:04                         ` Zachary Amsden
2005-11-15 16:06                           ` Arjan van de Ven
2005-11-15 16:10                             ` Dave Jones
2005-11-15 16:14                               ` H. Peter Anvin
2005-11-15 16:19                                 ` Dave Jones
2005-11-15 16:25                                   ` Arjan van de Ven
2005-11-15 16:34                                     ` Zachary Amsden
2005-11-15 16:28                                   ` H. Peter Anvin
2005-11-15 16:24                             ` Zachary Amsden
2005-11-15 16:52                               ` Linus Torvalds
2005-11-15 16:16                           ` Gerd Knorr
2005-11-15 16:08                         ` Roland Dreier
2005-11-16  9:58                           ` Gerd Knorr
2005-11-15 16:12                         ` Linus Torvalds
2005-11-15 16:16                           ` Dave Jones
2005-11-15 16:27                             ` Gerd Knorr
2005-11-16 16:12                         ` [RFC] SMP alternatives Gerd Knorr
2005-11-22 17:48                           ` [patch] " Gerd Knorr
2005-11-22 18:01                             ` Pavel Machek
2005-11-23 15:12                             ` Vincent Hanquez
2005-11-23 19:17                             ` Andi Kleen
2005-11-23 15:29                               ` Gerd Knorr
2005-11-23 16:42                               ` Alan Cox
2005-11-23 16:39                                 ` Andi Kleen
2005-11-23 17:21                                   ` Alan Cox
2005-11-23 16:59                                     ` Andi Kleen
2005-11-23 22:00                                       ` Alan Cox
2005-11-24 13:13                                         ` Andi Kleen
2005-11-24 13:30                                           ` Eric W. Biederman
2005-11-24 13:39                                             ` Andi Kleen
2005-11-24 13:58                                               ` Eric W. Biederman
2005-11-24 19:16                                                 ` thockin
2005-11-24 19:26                                                   ` Andi Kleen
2005-11-24 14:34                                               ` Alan Cox
2005-11-24 14:22                                                 ` Andi Kleen
2005-11-24 15:15                                                   ` Alan Cox
2005-11-24 14:55                                                     ` Andi Kleen
2005-11-24 15:09                                                       ` Eric W. Biederman
2005-11-24 15:36                                                         ` Andi Kleen
2005-11-24 16:49                                                           ` Eric W. Biederman
2005-11-24 19:12                                                           ` thockin
2005-11-24 19:14                                                             ` Andi Kleen
2005-11-24 19:24                                                               ` thockin
2005-11-24 19:29                                                                 ` Andi Kleen
2005-11-24 19:44                                                                   ` thockin
2005-11-24 21:20                                                                     ` Andi Kleen
2005-11-24 21:40                                                                       ` thockin
2005-11-24 23:33                                                                       ` Eric W. Biederman
2005-11-24 23:12                                                               ` Alan Cox
2005-11-24 22:48                                                                 ` thockin
2005-11-24 23:35                                                                   ` Andi Kleen
2005-11-25  0:13                                                                     ` Alan Cox
2005-11-25  1:33                                                                     ` H. Peter Anvin
2005-11-28 19:15                                                                     ` Bill Davidsen
2005-11-24 16:02                                                         ` Alan Cox
2005-11-24 19:09                                                     ` thockin
2005-11-24 14:30                                           ` Alan Cox
2005-11-23 17:02                                     ` Linus Torvalds
2005-11-23 18:02                                       ` H. Peter Anvin
2005-11-23 18:42                                         ` Linus Torvalds
2005-11-23 17:26                                           ` Jeff V. Merkey
2005-11-23 19:03                                             ` Linus Torvalds
2005-11-23 19:31                                               ` jmerkey
2005-11-23 18:46                                           ` Andi Kleen
2005-11-23 19:12                                           ` H. Peter Anvin
2005-11-23 19:30                                             ` jmerkey
2005-11-23 21:44                                           ` Alan Cox
2005-11-23 21:13                                             ` Andi Kleen
2005-11-23 21:46                                               ` Jeff Garzik
2005-11-23 22:23                                                 ` Andi Kleen
2005-11-23 22:30                                                 ` Pavel Machek
2005-11-23 22:05                                               ` Alan Cox
2005-11-23 21:36                                                 ` Arjan van de Ven
2005-11-23 21:36                                                 ` Andi Kleen
2005-11-23 22:13                                                 ` Linus Torvalds
2005-11-23 21:36                                             ` Linus Torvalds
2005-11-23 21:43                                               ` Andi Kleen
2005-11-23 22:15                                                 ` Linus Torvalds
2005-11-23 22:22                                                   ` Andi Kleen
2005-11-23 22:25                                                     ` H. Peter Anvin
2005-11-23 22:32                                                       ` Andi Kleen
2005-11-23 22:36                                                         ` H. Peter Anvin
2005-11-23 22:40                                                           ` Andi Kleen
2005-11-23 22:52                                                             ` H. Peter Anvin
2005-11-23 23:10                                                     ` Linus Torvalds
2005-11-24  0:55                                                 ` Jeff Garzik
2005-11-23 21:48                                               ` Daniel Jacobowitz
2005-11-23 21:53                                                 ` H. Peter Anvin
2005-11-23 22:03                                                   ` Daniel Jacobowitz
2005-11-23 22:09                                                     ` H. Peter Anvin
2005-11-23 22:21                                                       ` Linus Torvalds
2005-11-23 23:29                                                         ` Eric W. Biederman
2005-11-23 23:40                                                           ` Linus Torvalds
2005-11-23 22:19                                                 ` Linus Torvalds
2005-11-23 22:20                                                   ` Daniel Jacobowitz
2005-11-23 23:08                                                     ` Linus Torvalds
2005-11-23 23:02                                                       ` Jeff V. Merkey
2005-11-23 23:42                                                       ` Daniel Jacobowitz
2005-11-23 23:59                                                         ` Linus Torvalds
2005-11-24  2:06                                                           ` Daniel Jacobowitz
2005-11-24 22:32                                                         ` Ulrich Drepper
2005-11-28 19:58                                                         ` Bill Davidsen
2005-11-24  1:02                                                       ` Jeff Garzik
2005-11-24 13:01                                                       ` Pádraig Brady
2005-11-24 13:12                                                         ` Arjan van de Ven
2005-11-28 19:52                                                       ` Bill Davidsen
2005-11-28 20:05                                                         ` Zachary Amsden
2005-11-28 22:19                                                         ` Jeff V. Merkey
2005-11-28 23:00                                                           ` Zachary Amsden
2005-11-28 23:07                                                             ` H. Peter Anvin
2005-11-28 23:30                                                               ` Zachary Amsden
2005-11-28 23:32                                                                 ` H. Peter Anvin
2005-11-28 23:12                                                             ` Andi Kleen
2005-11-23 22:50                                               ` Alan Cox
2005-11-23 22:22                                                 ` H. Peter Anvin
2005-11-25  7:38                                               ` Chris Wedgwood
2005-11-25 17:33                                                 ` Linus Torvalds
2005-11-28 20:25                                                   ` Bill Davidsen
2005-11-25 20:13                                                 ` H. Peter Anvin
2005-11-24  3:23                                             ` Mikulas Patocka
2005-11-24  3:31                                           ` Mikulas Patocka
2005-11-24  3:55                                             ` H. Peter Anvin
2005-11-24 22:30                                           ` Ulrich Drepper
2005-11-23 16:43                                 ` Gerd Knorr
2005-11-23 16:51                                   ` H. Peter Anvin [this message]
2005-11-24 17:48 linux
2005-11-24 18:48 ` Linus Torvalds
2005-11-24 18:24 colin
2006-01-24 15:33 [PATCH] " Gerd Hoffmann
2006-01-24 16:22 ` Ben Collins
2006-01-25  9:20   ` Gerd Hoffmann
2006-01-26 10:22 ` Pavel Machek
2006-01-26 11:17   ` Gerd Hoffmann
2006-01-26 11:48     ` Pavel Machek

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