From owner-cvs-src@FreeBSD.ORG  Sat Mar 20 13:37:52 2004
Return-Path: <owner-cvs-src@FreeBSD.ORG>
Delivered-To: cvs-src@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id D149516A4CE; Sat, 20 Mar 2004 13:37:52 -0800 (PST)
Received: from cs.rice.edu (cs.rice.edu [128.42.1.30])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id AB0AF43D2D; Sat, 20 Mar 2004 13:37:52 -0800 (PST)
	(envelope-from alc@cs.rice.edu)
Received: from localhost (calypso.cs.rice.edu [128.42.1.127])
	by cs.rice.edu (Postfix) with ESMTP
	id E78F34AA8A; Sat, 20 Mar 2004 15:37:51 -0600 (CST)
Received: from cs.rice.edu ([128.42.1.30])
 by localhost (calypso.cs.rice.edu [128.42.1.127]) (amavisd-new, port 10024)
 with LMTP id 24569-01-19; Sat, 20 Mar 2004 15:37:51 -0600 (CST)
Received: by cs.rice.edu (Postfix, from userid 19572)
	id 6310A4ADC5; Sat, 20 Mar 2004 15:37:51 -0600 (CST)
Date: Sat, 20 Mar 2004 15:37:51 -0600
From: Alan Cox <alc@cs.rice.edu>
To: Nate Lawson <nate@root.org>
Message-ID: <20040320213751.GW6197@cs.rice.edu>
References: <20040320193633.8E25416A553@hub.freebsd.org>
	<20040320124836.Q23876@root.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20040320124836.Q23876@root.org>
User-Agent: Mutt/1.3.28i
X-Virus-Scanned: by amavis-20030616-p7 at cs.rice.edu
cc: Alan Cox <alc@FreeBSD.org>
cc: cvs-src@FreeBSD.org
cc: src-committers@FreeBSD.org
cc: cvs-all@FreeBSD.org
Subject: Re: cvs commit: src/sys/amd64/amd64 uio_machdep.c src/sys/conf
	files.amd64 src/sys/sys uio.h
X-BeenThere: cvs-src@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: CVS commit messages for the src tree <cvs-src.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-src>,
	<mailto:cvs-src-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/cvs-src>
List-Post: <mailto:cvs-src@freebsd.org>
List-Help: <mailto:cvs-src-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-src>,
	<mailto:cvs-src-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 20 Mar 2004 21:37:53 -0000

On Sat, Mar 20, 2004 at 12:50:12PM -0800, Nate Lawson wrote:
> On Sat, 20 Mar 2004, Alan Cox wrote:
> >   FreeBSD src repository
> >
> >   Modified files:
> >     sys/conf             files.amd64
> >     sys/sys              uio.h
> >   Added files:
> >     sys/amd64/amd64      uio_machdep.c
> >   Log:
> >   Introduce uiomove_fromphys().  This is a variant of uiomove() that takes
> >   a collection of physical pages as the source.  On amd64 it is implemented
> >   using the direct virtual-to-physical map.
> >
> >   Revision  Changes    Path
> >   1.1       +131 -0    src/sys/amd64/amd64/uio_machdep.c (new)
> >   1.30      +1 -0      src/sys/conf/files.amd64
> >   1.34      +3 -0      src/sys/sys/uio.h
> 
> Excellent.  FreeBSD hits the 21st century, where we flip back to P->V.
> 

The funny part is that I'm seeing even greater performance gains
from using this API on a 32-bit P4 Xeon.  There, we don't have
a direct virtual-to-physical mapping, so I use sf_buf_alloc() and
sf_buf_free().  For a prototype pipe reimplementation that eliminates
the ephemeral mappings and uses uiomove_fromphys(), the lmbench
pipe bandwidth is going from ~1GB/sec to ~1.7GB/sec.  This surprised
me at first, but it's consistent with Jeff R's reported numbers
for how expensive invlpg is on P4s.

Regards,
Alan