From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 27 Jun 2005 15:38:20 +0100 (BST) Received: from p549F652D.dip.t-dialin.net ([IPv6:::ffff:84.159.101.45]:52648 "EHLO bacchus.net.dhis.org") by linux-mips.org with ESMTP id ; Mon, 27 Jun 2005 15:38:01 +0100 Received: from dea.linux-mips.net (localhost.localdomain [127.0.0.1]) by bacchus.net.dhis.org (8.13.1/8.13.1) with ESMTP id j5REabSb008816; Mon, 27 Jun 2005 15:36:37 +0100 Received: (from ralf@localhost) by dea.linux-mips.net (8.13.1/8.13.1/Submit) id j5REaXPw008815; Mon, 27 Jun 2005 16:36:33 +0200 Date: Mon, 27 Jun 2005 16:36:33 +0200 From: Ralf Baechle To: "Maciej W. Rozycki" Cc: Thomas Bogendoerfer , Florian Lohoff , linux-mips@linux-mips.org Subject: Re: [patch] blast_scache nop for sc cpus without scache Message-ID: <20050627143633.GD28082@linux-mips.org> References: <20050625131938.GA7669@paradigm.rfc822.org> <20050625160316.GP6953@linux-mips.org> <20050625175048.GA25276@alpha.franken.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 8207 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Mon, Jun 27, 2005 at 01:45:39PM +0100, Maciej W. Rozycki wrote: > Anyway these days we apparently ignore the result of the S-cache probe > and the sc_present variable. The only values that determine whether an > S-cache is present or not are: cpu_has_dc_aliases, cpu_has_ic_fills_f_dc > and cpu_has_subset_pcaches which you need to get right for your > configuration -- I guess cpu_has_dc_aliases == 0, cpu_has_ic_fills_f_dc == > 1 and cpu_has_subset_pcaches == 0 should be right to fulfil your needs > (but it may break elsewhere). Have I heard: "serious brain damage" from > you? Well, I couldn't agree more... What matters isn't the presence of a second level cache but the actual properties. The old code was relying almost exclusively on the precense of an S-cache, so had to be very liberal in it's assumption about that cache's properties. Performancewise that sucked, badly. Ralf