From owner-freebsd-net Fri Oct 26 8:18: 0 2001 Delivered-To: freebsd-net@freebsd.org Received: from iguana.aciri.org (iguana.aciri.org [192.150.187.36]) by hub.freebsd.org (Postfix) with ESMTP id 8449437B406 for ; Fri, 26 Oct 2001 08:17:57 -0700 (PDT) Received: (from rizzo@localhost) by iguana.aciri.org (8.11.3/8.11.1) id f9QFESr65017; Fri, 26 Oct 2001 08:14:28 -0700 (PDT) (envelope-from rizzo) Date: Fri, 26 Oct 2001 08:14:28 -0700 From: Luigi Rizzo To: Ian Dowse Cc: David Malone , Keiichi SHIMA / ????????? , Bosko Milekic , Alfred Perlstein , net@FreeBSD.ORG Subject: Re: performance issues with M_PREPEND on clusters Message-ID: <20011026081428.D64631@iguana.aciri.org> References: <200110261310.aa66738@salmon.maths.tcd.ie> <200110261328.aa71753@salmon.maths.tcd.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200110261328.aa71753@salmon.maths.tcd.ie> User-Agent: Mutt/1.3.23i Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Fri, Oct 26, 2001 at 01:28:29PM +0100, Ian Dowse wrote: > In message <200110261310.aa66738@salmon.maths.tcd.ie>, David Malone writes: > > > >So the M_LEADINGSPACE macro should probaly read: > > > >#define M_LEADINGSPACE(m) > > \ > > (!M_WRITABLE(m) ? 0 : \ > > (m)->m_flags & M_EXT ? (m)->m_data - (m)->m_ext.ext_buf : \ > > (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \ > > (m)->m_data - (m)->m_dat) > > Yes, I think this is cleaner than the version that was just committed > to -stable, and it could have been committed to -current and MFC'd > in the normal way without changes. I really doubt that it is worth > splitting up M_WRITABLE just to marginally optimise M_LEADINGSPACE. gcc -O seems to agree with you :) This form produces a kernel which is 32 bytes shorter than the form that I committed (out of 1Meg, so not really a big deal). cheers luigi To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message