From owner-cvs-all@FreeBSD.ORG Wed Nov 10 18:53:16 2004 Return-Path: Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id BF23D16A4CE; Wed, 10 Nov 2004 18:53:16 +0000 (GMT) Received: from mail12.syd.optusnet.com.au (mail12.syd.optusnet.com.au [211.29.132.193]) by mx1.FreeBSD.org (Postfix) with ESMTP id 17C4343D5A; Wed, 10 Nov 2004 18:53:16 +0000 (GMT) (envelope-from PeterJeremy@optushome.com.au) Received: from cirb503493.alcatel.com.au (c211-30-75-229.belrs2.nsw.optusnet.com.au [211.30.75.229]) iAAIrDnW025699 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Thu, 11 Nov 2004 05:53:14 +1100 Received: from cirb503493.alcatel.com.au (localhost.alcatel.com.au [127.0.0.1])iAAIrDxP024051; Thu, 11 Nov 2004 05:53:13 +1100 (EST) (envelope-from pjeremy@cirb503493.alcatel.com.au) Received: (from pjeremy@localhost)iAAIrCgZ024050; Thu, 11 Nov 2004 05:53:12 +1100 (EST) (envelope-from pjeremy) Date: Thu, 11 Nov 2004 05:53:12 +1100 From: Peter Jeremy To: Alfred Perlstein Message-ID: <20041110185312.GO79646@cirb503493.alcatel.com.au> References: <4191062A.6090009@elischer.org> <1100024464.29384.30.camel@palm.tree.com> <41910D86.3080605@freebsd.org> <1100025632.29384.54.camel@palm.tree.com> <20041109201954.GO24892@elvis.mu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041109201954.GO24892@elvis.mu.org> User-Agent: Mutt/1.4.2i cc: Alan Cox cc: cvs-src@freebsd.org cc: cvs-all@freebsd.org cc: "src-committers @ freebsd. org John Baldwin" cc: Stephan Uphoff Subject: Re: cvs commit: src/sys/i386/i386 pmap.c X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Nov 2004 18:53:16 -0000 On Tue, 2004-Nov-09 12:19:54 -0800, Alfred Perlstein wrote: >* Stephan Uphoff [041109 10:43] wrote: >> >> Caugh, caugh ... yes that would be a fine name .... caugh, caugh > >Don't feel too bad, the original spl mechanism would talk to the >hardware, what you mentioned was an optimization that spl didn't >get until later. The SPL mechanism was an excellent fit for the PDP-11 (and M68K) which managed interrupt priorities within the CPU. On the PC, it was far more expensive because interrupt prioritisation was managed in the i8259's and required several io instructions to update. Moving to a software SPL was effectively just moving back to the PDP-11 approach (managing priorities within the CPU) though with the prioritisation explicitly coded rather than in the microcode. -- Peter Jeremy