From owner-freebsd-bugs@FreeBSD.ORG  Sun Jan 13 02:55:03 2008
Return-Path: <owner-freebsd-bugs@FreeBSD.ORG>
Delivered-To: freebsd-bugs@FreeBSD.ORG
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id EB57D16A417
	for <freebsd-bugs@FreeBSD.ORG>; Sun, 13 Jan 2008 02:55:03 +0000 (UTC)
	(envelope-from das@FreeBSD.ORG)
Received: from VARK.MIT.EDU (VARK.MIT.EDU [18.95.3.179])
	by mx1.freebsd.org (Postfix) with ESMTP id A2A0B13C458
	for <freebsd-bugs@FreeBSD.ORG>; Sun, 13 Jan 2008 02:55:03 +0000 (UTC)
	(envelope-from das@FreeBSD.ORG)
Received: from VARK.MIT.EDU (localhost [127.0.0.1])
	by VARK.MIT.EDU (8.14.2/8.14.1) with ESMTP id m0D2sxCf009850;
	Sat, 12 Jan 2008 21:54:59 -0500 (EST) (envelope-from das@FreeBSD.ORG)
Received: (from das@localhost)
	by VARK.MIT.EDU (8.14.2/8.14.1/Submit) id m0D2sxGW009849;
	Sat, 12 Jan 2008 21:54:59 -0500 (EST) (envelope-from das@FreeBSD.ORG)
Date: Sat, 12 Jan 2008 21:54:59 -0500
From: David Schultz <das@FreeBSD.ORG>
To: George Reid <greid@ukug.uk.freebsd.org>
Message-ID: <20080113025459.GA4582@VARK.MIT.EDU>
Mail-Followup-To: George Reid <greid@ukug.uk.freebsd.org>,
	freebsd-bugs@FreeBSD.ORG
References: <200705060041.l460fbgE041143@freefall.freebsd.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <200705060041.l460fbgE041143@freefall.freebsd.org>
Cc: freebsd-bugs@FreeBSD.ORG
Subject: Re: bin/22442: [PATCH] Increase speed of split(1)
X-BeenThere: freebsd-bugs@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Bug reports <freebsd-bugs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-bugs>,
	<mailto:freebsd-bugs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-bugs>
List-Post: <mailto:freebsd-bugs@freebsd.org>
List-Help: <mailto:freebsd-bugs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-bugs>,
	<mailto:freebsd-bugs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 13 Jan 2008 02:55:04 -0000

Hmm...I'm not seeing any measurable difference in -CURRENT in
either the cached or the uncached case. The sequential read-ahead
heuristic in the kernel seems to negate any benefit of using a
larger buffer size, and using a larger buffer just causes problems
when people try to split out larger files (e.g., multi-GB files
for transfer to removable media). Interesting idea, though...