From: Christoph Lameter <cl@linux-foundation.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Ingo Molnar <mingo@elte.hu>, Mike Travis <travis@sgi.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jack Steiner <steiner@sgi.com>,
linux-kernel@vger.kernel.org,
Arjan van de Ven <arjan@infradead.org>
Subject: Re: [RFC 00/15] x86_64: Optimize percpu accesses
Date: Thu, 10 Jul 2008 12:38:54 -0500 [thread overview]
Message-ID: <4876492E.90901@linux-foundation.org> (raw)
In-Reply-To: <m1prpl4pmh.fsf@frodo.ebiederm.org>
Eric W. Biederman wrote:
> First off right now reserving more than about 64KB is ridiculous. We rightly
> don't have that many per cpu variables.
We do. The case has been made numerous times that we need at least several megabytes of per cpu memory in case someone creates gazillions of ip tunnels etc etc.
>> instead of looking it up in a table because that will save a memory access on
>> per_cpu().
>
> ???? Optimizing per_cpu seems to be the wrong path. If you want to go fast you
> access the data on the cpu you start out on.
Yes most arches provide specialized registers for local per cpu variable access. There are cases though in which you have to access another processors cpu space.
>> Maybe there is another way of arranging things that would allow for this?
>
> Yes. Start with a patch that doesn't have freaky failures that can't be understood
> or bisected because the patch is too big. The only reason we are having a conversation
The patches are reasonably small. The problem that Mike seems to have is early boot debugging.
next prev parent reply other threads:[~2008-07-10 17:40 UTC|newest]
Thread overview: 190+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-09 16:51 [RFC 00/15] x86_64: Optimize percpu accesses Mike Travis
2008-07-09 16:51 ` [RFC 01/15] x86_64: Cleanup early setup_percpu references Mike Travis
2008-07-09 16:51 ` [RFC 02/15] x86_64: Fold pda into per cpu area Mike Travis
2008-07-09 22:02 ` Eric W. Biederman
2008-07-13 17:54 ` Ingo Molnar
2008-07-14 14:24 ` Mike Travis
2008-07-09 16:51 ` [RFC 03/15] x86_64: Reference zero-based percpu variables offset from gs Mike Travis
2008-07-09 16:51 ` [RFC 04/15] x86_64: Replace cpu_pda ops with percpu ops Mike Travis
2008-07-09 16:51 ` [RFC 05/15] x86_64: Replace xxx_pda() operations with x86_xxx_percpu() Mike Travis
2008-07-09 16:51 ` [RFC 06/15] x86_64: Replace xxx_pda() operations in include_asm-x86_current_h Mike Travis
2008-07-09 16:51 ` [RFC 07/15] x86_64: Replace xxx_pda() operations in include_asm-x86_hardirq_64_h Mike Travis
2008-07-09 16:51 ` [RFC 08/15] x86_64: Replace xxx_pda() operations in include_asm-x86_mmu_context_64_h Mike Travis
2008-07-09 16:51 ` [RFC 09/15] x86_64: Replace xxx_pda() operations in include_asm-x86_percpu_h Mike Travis
2008-07-09 16:51 ` [RFC 10/15] x86_64: Replace xxx_pda() operations in include_asm-x86_smp_h Mike Travis
2008-07-09 16:51 ` [RFC 11/15] x86_64: Replace xxx_pda() operations in include_asm-x86_stackprotector_h Mike Travis
2008-07-09 16:51 ` [RFC 12/15] x86_64: Replace xxx_pda() operations in include_asm-x86_thread_info_h Mike Travis
2008-07-09 16:51 ` [RFC 13/15] x86_64: Replace xxx_pda() operations in include_asm-x86_topology_h Mike Travis
2008-07-09 16:51 ` [RFC 14/15] x86_64: Remove xxx_pda() operations Mike Travis
2008-07-09 16:51 ` [RFC 15/15] x86_64: Remove cpu_pda() macro Mike Travis
2008-07-09 17:19 ` [RFC 00/15] x86_64: Optimize percpu accesses H. Peter Anvin
2008-07-09 17:40 ` Mike Travis
2008-07-09 17:42 ` H. Peter Anvin
2008-07-09 18:05 ` Mike Travis
2008-07-09 17:44 ` Jeremy Fitzhardinge
2008-07-09 18:09 ` Mike Travis
2008-07-09 18:30 ` H. Peter Anvin
2008-07-09 19:34 ` Ingo Molnar
2008-07-09 19:44 ` H. Peter Anvin
2008-07-09 20:26 ` Adrian Bunk
2008-07-09 21:03 ` Mike Travis
2008-07-09 21:23 ` Jeremy Fitzhardinge
2008-07-25 15:49 ` Mike Travis
2008-07-25 16:08 ` Jeremy Fitzhardinge
2008-07-25 16:46 ` Mike Travis
2008-07-25 16:58 ` Jeremy Fitzhardinge
2008-07-25 18:12 ` Mike Travis
2008-07-09 17:27 ` Jeremy Fitzhardinge
2008-07-09 17:39 ` Christoph Lameter
2008-07-09 17:51 ` Jeremy Fitzhardinge
2008-07-09 18:14 ` Mike Travis
2008-07-09 18:22 ` Jeremy Fitzhardinge
2008-07-09 18:31 ` Mike Travis
2008-07-09 19:08 ` Jeremy Fitzhardinge
2008-07-09 18:02 ` Mike Travis
2008-07-09 18:13 ` Christoph Lameter
2008-07-09 18:26 ` Jeremy Fitzhardinge
2008-07-09 18:34 ` Christoph Lameter
2008-07-09 18:37 ` H. Peter Anvin
2008-07-09 18:48 ` Jeremy Fitzhardinge
2008-07-09 18:53 ` Christoph Lameter
2008-07-09 19:07 ` Jeremy Fitzhardinge
2008-07-09 19:12 ` Christoph Lameter
2008-07-09 19:32 ` Jeremy Fitzhardinge
2008-07-09 19:41 ` Ingo Molnar
2008-07-09 19:45 ` H. Peter Anvin
2008-07-09 19:52 ` Christoph Lameter
2008-07-09 20:00 ` Ingo Molnar
2008-07-09 20:09 ` Jeremy Fitzhardinge
2008-07-09 21:05 ` Mike Travis
2008-07-09 19:44 ` Christoph Lameter
2008-07-09 19:48 ` Jeremy Fitzhardinge
2008-07-09 18:27 ` Mike Travis
2008-07-09 18:46 ` Jeremy Fitzhardinge
2008-07-09 20:22 ` Eric W. Biederman
2008-07-09 20:35 ` Jeremy Fitzhardinge
2008-07-09 20:53 ` Eric W. Biederman
2008-07-09 21:03 ` Ingo Molnar
2008-07-09 21:16 ` H. Peter Anvin
2008-07-09 21:10 ` Arjan van de Ven
2008-07-09 23:20 ` Eric W. Biederman
2008-07-09 18:31 ` H. Peter Anvin
2008-07-09 18:00 ` Mike Travis
2008-07-09 19:05 ` Jeremy Fitzhardinge
2008-07-09 19:28 ` Ingo Molnar
2008-07-09 20:55 ` Mike Travis
2008-07-09 21:12 ` Ingo Molnar
2008-07-09 20:00 ` Eric W. Biederman
2008-07-09 20:05 ` Jeremy Fitzhardinge
2008-07-09 20:15 ` Ingo Molnar
2008-07-09 20:07 ` Ingo Molnar
2008-07-09 20:11 ` Jeremy Fitzhardinge
2008-07-09 20:18 ` Christoph Lameter
2008-07-09 20:33 ` Jeremy Fitzhardinge
2008-07-09 20:42 ` H. Peter Anvin
2008-07-09 20:48 ` Jeremy Fitzhardinge
2008-07-09 21:06 ` Eric W. Biederman
2008-07-09 21:16 ` H. Peter Anvin
2008-07-09 21:20 ` Jeremy Fitzhardinge
2008-07-09 21:25 ` Christoph Lameter
2008-07-09 21:36 ` H. Peter Anvin
2008-07-09 21:41 ` Jeremy Fitzhardinge
2008-07-09 22:22 ` Eric W. Biederman
2008-07-09 22:32 ` Jeremy Fitzhardinge
2008-07-09 23:36 ` Eric W. Biederman
2008-07-10 0:19 ` H. Peter Anvin
2008-07-10 0:24 ` Jeremy Fitzhardinge
2008-07-10 14:14 ` Christoph Lameter
2008-07-10 14:26 ` H. Peter Anvin
2008-07-10 15:26 ` Christoph Lameter
2008-07-10 15:42 ` H. Peter Anvin
2008-07-10 16:24 ` Christoph Lameter
2008-07-10 16:33 ` H. Peter Anvin
2008-07-10 16:45 ` Christoph Lameter
2008-07-10 17:33 ` Jeremy Fitzhardinge
2008-07-10 17:42 ` Christoph Lameter
2008-07-10 17:53 ` Jeremy Fitzhardinge
2008-07-10 17:55 ` H. Peter Anvin
2008-07-10 20:52 ` Christoph Lameter
2008-07-10 20:58 ` Jeremy Fitzhardinge
2008-07-10 21:03 ` H. Peter Anvin
2008-07-11 0:55 ` Mike Travis
2008-07-10 21:05 ` Christoph Lameter
2008-07-10 21:22 ` Eric W. Biederman
2008-07-10 21:29 ` H. Peter Anvin
2008-07-11 0:12 ` Mike Travis
2008-07-11 0:14 ` H. Peter Anvin
2008-07-11 0:58 ` Mike Travis
2008-07-11 1:41 ` H. Peter Anvin
2008-07-11 15:37 ` Christoph Lameter
2008-07-11 0:42 ` Eric W. Biederman
2008-07-11 15:36 ` Christoph Lameter
2008-07-10 17:53 ` H. Peter Anvin
2008-07-10 17:26 ` Eric W. Biederman
2008-07-10 17:38 ` Christoph Lameter [this message]
2008-07-10 19:11 ` Mike Travis
2008-07-10 19:12 ` Eric W. Biederman
2008-07-10 17:46 ` Mike Travis
2008-07-10 17:51 ` H. Peter Anvin
2008-07-10 19:09 ` Eric W. Biederman
2008-07-10 19:18 ` Mike Travis
2008-07-10 19:32 ` H. Peter Anvin
2008-07-10 23:37 ` Mike Travis
2008-07-10 20:17 ` Eric W. Biederman
2008-07-10 20:24 ` Ingo Molnar
2008-07-10 21:33 ` Eric W. Biederman
2008-07-11 1:39 ` Mike Travis
2008-07-11 2:57 ` Eric W. Biederman
2008-07-10 0:23 ` Jeremy Fitzhardinge
2008-07-09 20:35 ` H. Peter Anvin
2008-07-09 20:39 ` Arjan van de Ven
2008-07-09 20:44 ` H. Peter Anvin
2008-07-09 20:50 ` Jeremy Fitzhardinge
2008-07-09 21:12 ` H. Peter Anvin
2008-07-09 21:26 ` Jeremy Fitzhardinge
2008-07-09 21:37 ` H. Peter Anvin
2008-07-09 22:10 ` Eric W. Biederman
2008-07-09 22:23 ` H. Peter Anvin
2008-07-09 23:54 ` Eric W. Biederman
2008-07-10 16:22 ` Mike Travis
2008-07-10 16:25 ` H. Peter Anvin
2008-07-10 16:35 ` Christoph Lameter
2008-07-10 16:39 ` H. Peter Anvin
2008-07-10 16:47 ` Christoph Lameter
2008-07-10 17:21 ` Jeremy Fitzhardinge
2008-07-10 17:31 ` Christoph Lameter
2008-07-10 17:48 ` Jeremy Fitzhardinge
2008-07-10 18:00 ` H. Peter Anvin
2008-07-10 17:20 ` Mike Travis
2008-07-10 17:07 ` Jeremy Fitzhardinge
2008-07-10 17:12 ` Christoph Lameter
2008-07-10 17:25 ` Jeremy Fitzhardinge
2008-07-10 17:34 ` Christoph Lameter
2008-07-10 17:41 ` Mike Travis
2008-07-10 18:01 ` H. Peter Anvin
2008-07-10 20:51 ` Christoph Lameter
2008-07-10 20:58 ` H. Peter Anvin
2008-07-10 21:07 ` Christoph Lameter
2008-07-10 21:11 ` H. Peter Anvin
2008-07-11 15:32 ` Christoph Lameter
2008-07-11 16:07 ` H. Peter Anvin
2008-07-11 16:57 ` Eric W. Biederman
2008-07-11 17:10 ` H. Peter Anvin
2008-07-10 21:26 ` Eric W. Biederman
2008-07-10 18:48 ` Eric W. Biederman
2008-07-10 18:54 ` Jeremy Fitzhardinge
2008-07-10 19:18 ` Eric W. Biederman
2008-07-10 19:56 ` Jeremy Fitzhardinge
2008-07-10 20:22 ` Eric W. Biederman
2008-07-10 20:54 ` Jeremy Fitzhardinge
2008-07-11 6:59 ` Rusty Russell
2008-07-10 20:25 ` Eric W. Biederman
2008-07-10 17:57 ` H. Peter Anvin
2008-07-10 18:08 ` H. Peter Anvin
2008-07-09 20:46 ` Jeremy Fitzhardinge
2008-07-09 20:14 ` Arjan van de Ven
2008-07-09 20:33 ` Eric W. Biederman
2008-07-09 21:01 ` Ingo Molnar
2008-07-09 21:39 ` Mike Travis
2008-07-09 21:47 ` Jeremy Fitzhardinge
2008-07-09 21:55 ` Eric W. Biederman
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