Date: Fri, 26 Oct 2001 08:14:28 -0700 From: Luigi Rizzo <rizzo@aciri.org> To: Ian Dowse <iedowse@maths.tcd.ie> Cc: David Malone <dwmalone@maths.tcd.ie>, Keiichi SHIMA / ????????? <keiichi@iij.ad.jp>, Bosko Milekic <bmilekic@technokratis.com>, Alfred Perlstein <bright@mu.org>, net@FreeBSD.ORG Subject: Re: performance issues with M_PREPEND on clusters Message-ID: <20011026081428.D64631@iguana.aciri.org> In-Reply-To: <200110261328.aa71753@salmon.maths.tcd.ie> References: <200110261310.aa66738@salmon.maths.tcd.ie> <200110261328.aa71753@salmon.maths.tcd.ie>
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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
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