From owner-cvs-all  Tue Jun 26 17:56:53 2001
Delivered-To: cvs-all@freebsd.org
Received: from netau1.alcanet.com.au (ntp.alcanet.com.au [203.62.196.27])
	by hub.freebsd.org (Postfix) with ESMTP
	id 2F11337B405; Tue, 26 Jun 2001 17:56:47 -0700 (PDT)
	(envelope-from jeremyp@gsmx07.alcatel.com.au)
Received: from mfg1.cim.alcatel.com.au (mfg1.cim.alcatel.com.au [139.188.23.1])
	by netau1.alcanet.com.au (8.9.3 (PHNE_22672)/8.9.3) with ESMTP id KAA25911;
	Wed, 27 Jun 2001 10:56:35 +1000 (EST)
Received: from gsmx07.alcatel.com.au by cim.alcatel.com.au
 (PMDF V5.2-32 #37645) with ESMTP id <01K59C2EG5M8VNZ1K1@cim.alcatel.com.au>;
 Wed, 27 Jun 2001 10:56:25 +1000
Received: (from jeremyp@localhost)	by gsmx07.alcatel.com.au (8.11.1/8.11.1)
 id f5R0uUD94300; Wed, 27 Jun 2001 10:56:31 +1000 (EST envelope-from jeremyp)
Content-return: prohibited
Date: Wed, 27 Jun 2001 10:56:30 +1000
From: Peter Jeremy <peter.jeremy@alcatel.com.au>
Subject: Re: Inline optimized bzero (was Re: cvs commit: src/sys/netinet
 tcp_subr.c)
In-reply-to: <200106241549.f5OFn6J78347@earth.backplane.com>; from
 dillon@earth.backplane.com on Sun, Jun 24, 2001 at 08:49:06AM -0700
To: Matt Dillon <dillon@earth.backplane.com>
Cc: Bruce Evans <bde@zeta.org.au>, cvs-committers@FreeBSD.ORG,
	cvs-all@FreeBSD.ORG
Mail-Followup-To: Matt Dillon <dillon@earth.backplane.com>,
	Bruce Evans <bde@zeta.org.au>, cvs-committers@FreeBSD.ORG,
	cvs-all@FreeBSD.ORG
Message-id: <20010627105630.B93007@gsmx07.alcatel.com.au>
MIME-version: 1.0
Content-type: text/plain; charset=us-ascii
Content-disposition: inline
User-Agent: Mutt/1.2.5i
References: <Pine.BSF.4.21.0106241725360.54646-100000@besplex.bde.org>
 <200106241549.f5OFn6J78347@earth.backplane.com>
Sender: owner-cvs-all@FreeBSD.ORG
Precedence: bulk
List-ID: <cvs-all.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo?subject=subscribe%20cvs-all>
List-Unsubscribe: <mailto:majordomo?subject=unsubscribe%20cvs-all>
X-Loop: FreeBSD.ORG

On 2001-Jun-24 08:49:06 -0700, Matt Dillon <dillon@earth.backplane.com> wrote:
>    I suppose the bzero() inline could implemented in the machine-dependant
>    code section.  It seems a shame to waste mostly portable code though.
>    I'll mess around with it a bit.

Anecdotal evidence (which isn't very trustworthy) suggests that a Unix
kernel spends a significant amount of time copying or zeroing bytes.
If this is true, it would be worthwhile having tweaked MD routines for
bcopy() and bzero().  One advantage being that at least some
architectures have instructions which are designed to copy or zero large
blocks of data without totally wiping L1 (and maybe L2) cache.

Peter

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe cvs-all" in the body of the message