From: Dave Hansen <hansendc@us.ibm.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: 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: Mon, 02 Apr 2007 13:13:17 -0700 [thread overview]
Message-ID: <1175544797.22373.62.camel@localhost.localdomain> (raw)
In-Reply-To: <Pine.LNX.4.64.0704020832320.30394@schroedinger.engr.sgi.com>
On Mon, 2007-04-02 at 08:37 -0700, Christoph Lameter wrote:
> You want a benchmark to prove that the removal of memory references and
> code improves performance?
Yes, please. ;)
I completely agree, it looks like it should be faster. The code
certainly has potential benefits. But, to add this neato, apparently
more performant feature, we unfortunately have to add code. Adding the
code has a cost: code maintenance. This isn't a runtime cost, but it is
a real, honest to goodness tradeoff.
So, let's get some kind of concrete idea what the tradeoffs are. Is it,
400 lines of code gets us a 10% performance boost across the board, or
that 400,000 lines gets us 0.1% on one specialized benchmark?
BTW, I like the patches. Very nice and clean.
-- Dave
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next prev parent reply other threads:[~2007-04-02 20:13 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 [this message]
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
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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