From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from colo.lackof.org (colo.lackof.org [198.49.126.79]) by dsl2.external.hp.com (Postfix) with ESMTP id 7C346488A for ; Sat, 21 Feb 2004 23:21:06 -0700 (MST) Date: Sat, 21 Feb 2004 23:21:05 -0700 From: Grant Grundler To: Stuart Brady Subject: Re: [parisc-linux] Hanging with kernels >= 2.4.22 Message-ID: <20040222062105.GF30849@colo.lackof.org> References: <20040218235225.GA1623@calypso> <20040219062907.GC13916@colo.lackof.org> <20040221075849.GA1642@calypso> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20040221075849.GA1642@calypso> Cc: parisc-linux@lists.parisc-linux.org List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, Feb 21, 2004 at 07:58:49AM +0000, Stuart Brady wrote: > Thanks! Changing NCR_700_MAX_TAGS to 1 in drivers/scsi/53c700.h did the > trick. Will I now have poor disk performance? If so, might I get away > with setting it to something higher, like 2 or 4, maybe? You can try, but I don't think it's worth it. > I've not heard of tagged command queues before - the idea seems to be to > transfer data to the drive as early as possible, but make decisions as > to what should be written first at a later stage. Is that correct? Sort of yes. The reasons are a bit more complicated than that. Key reasons are better utilization of disk buffer (w/o enabling WCE) and allow disk firmware to optimize for maximum throughput. There are tradeoffs and caveats to both. > > Maybe a FAQ entry for "715/xxx hangs" could be your first contribution? > > That's a good idea. Where should I send the entry? Here? Yes please. Making a diff against the file carlos pointed at would be easiest for me. But I'll take a single paragraph in plain text as well. The FAQ entry should mention which machines/SCSI controllers/disks are affected and how to set the queuedepth. Anything else is extra credit and I reserve the right to edit it out. :^) thanks, grant > -- > Stuart Brady > _______________________________________________ > parisc-linux mailing list > parisc-linux@lists.parisc-linux.org > http://lists.parisc-linux.org/mailman/listinfo/parisc-linux