From: michael@optusnet.com.au
To: Andi Kleen <ak@muc.de>
Cc: Denis Vlasenko <vda@ilport.com.ua>,
dean gaudet <dean-list-linux-kernel@arctic.org>,
Jeff Garzik <jgarzik@pobox.com>,
Benjamin LaHaise <bcrl@kvack.org>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC] x86-64: Use SSE for copy_page and clear_page
Date: 01 Jun 2005 17:22:28 +1000 [thread overview]
Message-ID: <m2zmuaee2z.fsf@mo.optusnet.com.au> (raw)
In-Reply-To: <20050531092358.GA9372@muc.de>
Andi Kleen <ak@muc.de> writes:
> > Thus with "normal" page clear and "nt" page copy routines
> > both clear and copy benchmarks run faster than with
> > stock kernel, both with small and large working set.
> >
> > Am I wrong?
>
> fork is only a corner case. The main case is a process allocating
> memory using brk/mmap and then using it.
Key point: "using it". This normally involves writes to memory. Most
applications don't commonly read memory that they haven't previously
written to. (valgrind et al call that behaviour a "bug" :).
Given that, I'd say you really don't want the page zero routines
touching the cache.
Michael.
next prev parent reply other threads:[~2005-06-01 7:24 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-30 18:16 [RFC] x86-64: Use SSE for copy_page and clear_page Benjamin LaHaise
2005-05-30 18:45 ` Jeff Garzik
2005-05-30 19:06 ` dean gaudet
2005-05-30 19:11 ` dean gaudet
2005-05-30 19:32 ` Andi Kleen
2005-05-31 8:37 ` Denis Vlasenko
2005-05-31 9:15 ` Denis Vlasenko
2005-05-31 9:23 ` Andi Kleen
2005-05-31 13:59 ` Benjamin LaHaise
2005-06-01 6:22 ` Denis Vlasenko
2005-06-01 6:47 ` Denis Vlasenko
2005-06-01 7:22 ` michael [this message]
2005-06-01 7:48 ` Andi Kleen
2005-06-01 7:48 ` Denis Vlasenko
2005-06-01 21:46 ` dean gaudet
2005-06-01 8:01 ` Nick Piggin
2005-05-30 19:38 ` Andi Kleen
2005-05-30 20:05 ` Michael Thonke
2005-05-30 20:14 ` Benjamin LaHaise
2005-05-30 20:42 ` Michael Thonke
2005-05-31 7:11 ` Andi Kleen
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