From: Christoph Lameter <clameter@sgi.com>
To: Bob Picco <bob.picco@hp.com>
Cc: Dave Hansen <hansendc@us.ibm.com>, Andi Kleen <ak@suse.de>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
Martin Bligh <mbligh@google.com>,
linux-mm@kvack.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH 1/4] x86_64: Switch to SPARSE_VIRTUAL
Date: Wed, 4 Apr 2007 15:38:28 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0704041531290.8127@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <20070404212736.GI10084@localhost>
On Wed, 4 Apr 2007, Bob Picco wrote:
> Well you must have forgotten about these two postings in regards to
> performance numbers:
> http://marc.info/?l=linux-ia64&m=111990276501051&w=2
> and
> http://marc.info/?l=linux-kernel&m=116664638611634&w=2
I am well aware of those but those were done with a PAGE_SIZE vmemmap
which is particularly bad on IA64 given the TLB fault overhead. You
eliminated the TLB fault overhead. Virtual Memmaps need to be designed in
such a way that they do not create additional overhead. The x86_64 version
here has no such overhead that you could eliminate with lookup tables.
The bad thing is that this benchmark then was used to justify
sparsemem on other platforms where such overhead does not exist.
One needs to be careful with benchmarks..... Its better to review the
code.
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next prev parent reply other threads:[~2007-04-04 22:38 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-01 7:10 [PATCH 1/2] Generic Virtual Memmap suport for SPARSEMEM Christoph Lameter
2007-04-01 7:10 ` [PATCH 1/4] x86_64: Switch to SPARSE_VIRTUAL Christoph Lameter
2007-04-01 7:11 ` Christoph Lameter
2007-04-01 10:46 ` Andi Kleen
2007-04-02 15:37 ` Christoph Lameter
2007-04-02 15:44 ` Andi Kleen
2007-04-02 15:51 ` Martin J. Bligh
2007-04-02 15:54 ` Christoph Lameter
2007-04-02 17:14 ` Andi Kleen
2007-04-02 17:34 ` Christoph Lameter
2007-04-02 19:54 ` Dave Hansen
2007-04-02 20:11 ` Christoph Lameter
2007-04-02 20:13 ` Dave Hansen
2007-04-02 20:30 ` Christoph Lameter
2007-04-02 20:38 ` Martin Bligh
2007-04-02 20:51 ` Christoph Lameter
2007-04-05 11:50 ` Andy Whitcroft
2007-04-05 18:27 ` Christoph Lameter
2007-04-07 22:06 ` [PATCH 1/4] x86_64: (SPARSE_VIRTUAL doubles sparsemem speed) Christoph Lameter
2007-04-07 22:18 ` Andi Kleen
2007-04-09 16:40 ` William Lee Irwin III
2007-04-09 17:16 ` Christoph Lameter
2007-04-09 18:20 ` William Lee Irwin III
2007-04-02 21:08 ` [PATCH 1/4] x86_64: Switch to SPARSE_VIRTUAL Dave Hansen
2007-04-02 21:28 ` Christoph Lameter
2007-04-02 21:43 ` Martin Bligh
2007-04-02 21:56 ` Dave Hansen
2007-04-02 22:29 ` Christoph Lameter
2007-04-02 22:31 ` Andi Kleen
2007-04-02 22:37 ` Christoph Lameter
2007-04-02 22:41 ` Martin Bligh
2007-04-02 22:49 ` Christoph Lameter
2007-04-02 22:52 ` Martin Bligh
2007-04-05 12:07 ` Andy Whitcroft
2007-04-04 21:27 ` Bob Picco
2007-04-04 22:38 ` Christoph Lameter [this message]
2007-04-02 23:03 ` Bjorn Helgaas
2007-04-02 15:44 ` Christoph Lameter
2007-04-02 16:18 ` Christoph Lameter
2007-04-02 20:50 ` [PATCH 1/2] Generic Virtual Memmap suport for SPARSEMEM Dave Hansen
2007-04-02 21:00 ` Christoph Lameter
2007-04-02 21:22 ` Dave Hansen
2007-04-02 21:31 ` Christoph Lameter
2007-04-02 21:42 ` Dave Hansen
2007-04-02 21:53 ` Christoph Lameter
2007-04-02 22:05 ` Dave Hansen
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