From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Persvold Date: Mon, 10 Sep 2001 15:26:47 +0000 Subject: Re: [Linux-ia64] Re: Write Combining (Write Coalescing) on memory mapped Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org David Mosberger wrote: > > >>>>> On Mon, 10 Sep 2001 16:16:31 +0200, Steffen Persvold said: > > Steffen> Steffen Persvold wrote: > > >> Do you think it's easier to set up a region which is mapped all > >> the time, so that ioremap_nocache() uses the already defined > >> region 6 for uncached accesses and ioremap() uses this new region > >> with "Write Coalescing" enabled ? How should I proceed to > >> introduce such a region ? > > Steffen> I haven't received any response. Does that mean that you > Steffen> guys don't even care about this issue ?? > > I thought I had answered this already: I don't think it's worthwhile > to use up another region for write combining mappings. There are no > free regions at the moment at any rate. It's quite possible that > we'll get rid of the uncached region at some point in the future as > well. > OK, so what you're saying is that the final solution is to use a i386 kind of approach to the problem ? This is what my original post (which included a patch) tried to do, but I didn't get it too work. I know you gave me feedback on this David, saying that it just may need some debugging. Does anyone on the list have the time to just look through the patch and try to analyze what's going wrong (or maybe just give me some hints on what to look for) ? The Oops I get is : "Unable to handle kernel paging request at virtual address 0xa00000000015c000" Thanks, -- Steffen Persvold | Scali Computer AS | Try out the world's best mailto:sp@scali.no | http://www.scali.com | performing MPI implementation: Tel: (+47) 2262 8950 | Olaf Helsets vei 6 | - ScaMPI 1.12.2 - Fax: (+47) 2262 8951 | N0621 Oslo, NORWAY | >300MBytes/s and <4uS latency