From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f48.google.com (mail-qg0-f48.google.com [209.85.192.48]) by kanga.kvack.org (Postfix) with ESMTP id 8FBC96B0032 for ; Fri, 24 Apr 2015 10:55:06 -0400 (EDT) Received: by qgeb100 with SMTP id b100so23777339qge.3 for ; Fri, 24 Apr 2015 07:55:06 -0700 (PDT) Received: from e37.co.us.ibm.com (e37.co.us.ibm.com. [32.97.110.158]) by mx.google.com with ESMTPS id j4si11610367qga.33.2015.04.24.07.55.05 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 24 Apr 2015 07:55:05 -0700 (PDT) Received: from /spool/local by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 24 Apr 2015 08:55:04 -0600 Received: from b03cxnp08028.gho.boulder.ibm.com (b03cxnp08028.gho.boulder.ibm.com [9.17.130.20]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id ED13F1FF001F for ; Fri, 24 Apr 2015 08:46:11 -0600 (MDT) Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by b03cxnp08028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t3OEsg7v40960188 for ; Fri, 24 Apr 2015 07:54:42 -0700 Received: from d03av05.boulder.ibm.com (localhost [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t3OEt0U8031376 for ; Fri, 24 Apr 2015 08:55:00 -0600 Date: Fri, 24 Apr 2015 07:54:59 -0700 From: "Paul E. McKenney" Subject: Re: Interacting with coherent memory on external devices Message-ID: <20150424145459.GY5561@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1429663372.27410.75.camel@kernel.crashing.org> <20150422005757.GP5561@linux.vnet.ibm.com> <1429664686.27410.84.camel@kernel.crashing.org> <20150422163135.GA4062@gmail.com> <1429756456.4915.22.camel@kernel.crashing.org> <20150423185240.GO5561@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Benjamin Herrenschmidt , Jerome Glisse , linux-kernel@vger.kernel.org, linux-mm@kvack.org, jglisse@redhat.com, mgorman@suse.de, aarcange@redhat.com, riel@redhat.com, airlied@redhat.com, aneesh.kumar@linux.vnet.ibm.com, Cameron Buschardt , Mark Hairgrove , Geoffrey Gerfin , John McKenna , akpm@linux-foundation.org On Fri, Apr 24, 2015 at 09:30:40AM -0500, Christoph Lameter wrote: > On Thu, 23 Apr 2015, Paul E. McKenney wrote: > > > If by "entire industry" you mean everyone who might want to use hardware > > acceleration, for example, including mechanical computer-aided design, > > I am skeptical. > > The industry designs GPUs with super fast special ram and accellerators > with special ram designed to do fast searches and you think you can demand page > that stuff in from the main processor? The demand paging is indeed a drawback for the option of using autonuma to handle the migration. And again, this is not intended to replace the careful hand-tuning that is required to get the last drop of performance out of the system. It is instead intended to handle the cases where the application needs substantially more performance than the CPUs alone can deliver, but where the cost of full-fledge hand tuning cannot be justified. You seem to believe that this latter category is the empty set, which I must confess does greatly surprise me. Thanx, Paul -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org