From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 27 Nov 2007 14:13:45 +0000 (GMT) Received: from localhost.localdomain ([127.0.0.1]:45774 "EHLO dl5rb.ham-radio-op.net") by ftp.linux-mips.org with ESMTP id S20026336AbXK0ONn (ORCPT ); Tue, 27 Nov 2007 14:13:43 +0000 Received: from denk.linux-mips.net (denk.linux-mips.net [127.0.0.1]) by dl5rb.ham-radio-op.net (8.14.1/8.13.8) with ESMTP id lAREDfCB019387; Tue, 27 Nov 2007 14:13:41 GMT Received: (from ralf@localhost) by denk.linux-mips.net (8.14.1/8.14.1/Submit) id lAREDfPk019386; Tue, 27 Nov 2007 14:13:41 GMT Date: Tue, 27 Nov 2007 14:13:41 +0000 From: Ralf Baechle To: Thomas Bogendoerfer Cc: linux-mips@linux-mips.org Subject: Re: SGI IP28 support Message-ID: <20071127141341.GA19316@linux-mips.org> References: <20071126223814.GA21339@alpha.franken.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071126223814.GA21339@alpha.franken.de> User-Agent: Mutt/1.5.17 (2007-11-01) 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: 17609 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, Nov 26, 2007 at 11:38:14PM +0100, Thomas Bogendoerfer wrote: > I finally cleaned up Peter Fuerst's IP28 patches and solved some of > the IP28 issues in an IMHO more eye-friendly way (no ip26ucmem). > My IP28 boots with these patches from an Debian sarge NFS root and > is able to dd data from the harddrive. I'm going to send this patches > to this list and the subsystem maintainers. > > There is one change missing to get a working SCSI driver, because > a proper fix will be done in 2.6.25. The quick&dirty workaround is > below. The workaround makes sure that the sense_buffer lives in > its own cache line by aligning and extendin it. > > The patch "Use real cache invalidate" still contains one problem. > It will not flush the cache correctly, if the given size is bigger > than the second level cache. The problem is, that there is no index > invalidate cache operation available. I have two ideas to solve that. > One is to always do a range invalidate (maybe just by using this only > for R10k machines, which usually have quite big caches) or scan through > the cache and use the tag informations to do hit invalidate. If anybody > has a better idea please speak up :-) A while ago I instrumented the cacheflushing functions to get a histogram of cacheflush sizes. I was surprised to find no flushes larger than 64K even though I did that experiment on an Origin with a large RAID array copying huge amounts of data with reads and writes of several MB. So as long as that finding holds your code will work. Ralf