From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Date: Mon, 01 Nov 2004 17:16:49 +0000 Subject: Re: [PATCH] top level scheduler domain for ia64 Message-Id: <20041101171649.GT8958@parcelfarce.linux.theplanet.co.uk> List-Id: References: <200410191427.27336.jbarnes@engr.sgi.com> In-Reply-To: <200410191427.27336.jbarnes@engr.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org On Mon, Nov 01, 2004 at 09:07:32AM -0800, Jesse Barnes wrote: > If I understand you right, you don't want a top level domain for your 32 way > systems, but you *do* want the node domains to span the whole thing. Is that > right? > > If so, you could do something like this I think? > > if (numnodes <= SMALL_SYSTEM_THRESHOLD) { > SD_NODES_PER_DOMAIN = numnodes; > build_node_domains(); /* each one spans the system */ > } else { > SD_NODES_PER_DOMAIN = 4; /* or whatever */ > build_node_domains(); /* only spans nearby nodes */ > build_top_level_domain(); /* whole system, infrequently balanced */ > } > > Would that address your concerns? Doesn't sound like a great idea. HP's already shipping 128-way Superdome IA-64 systems, and they'll want to be set up rather differently from the Altix systems. I think this code needs to be autotuning so it doesn't need to be touched whenever a vendor releases a new configuration (I think I heard that NASA's Altixes had a custom CPU brick with twice the CPUs in it?) -- "Next the statesmen will invent cheap lies, putting the blame upon the nation that is attacked, and every man will be glad of those conscience-soothing falsities, and will diligently study them, and refuse to examine any refutations of them; and thus he will by and by convince himself that the war is just, and will thank God for the better sleep he enjoys after this process of grotesque self-deception." -- Mark Twain