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Date:      Mon, 12 Apr 2010 08:00:23 -0700
From:      Jeremy Chadwick <freebsd@jdc.parodius.com>
To:        Andriy Gapon <avg@icyb.net.ua>
Cc:        Maho NAKATA <chat95@mac.com>, freebsd-stable@freebsd.org
Subject:   Re: Only 70% of theoretical peak performance on FreeBSD 8/amd64, Corei7 920
Message-ID:  <20100412150023.GA80292@icarus.home.lan>
In-Reply-To: <4BC3311F.5060503@icyb.net.ua>
References:  <20100412.131213.4959786962516027.chat95@mac.com> <4BC3311F.5060503@icyb.net.ua>

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On Mon, Apr 12, 2010 at 05:41:35PM +0300, Andriy Gapon wrote:
> Perhaps, he talks about support of large pages (2M) and related improvements in
> TLB performance.  If so, he (and you) may read about 'superpages' feature of FreeBSD.
> I am not sure if it is enabled by default in 8.0, you can check vm.pmap.pg_ps_enabled.

On 8.0-RELEASE and later, they are.  Line 183:

http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/amd64/amd64/pmap.c?annotate=1.667.2.12

Commit where they got enabled by default (approx. 16 months ago):

http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/amd64/amd64/pmap.c#rev1.646

-- 
| Jeremy Chadwick                                   jdc@parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |




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