From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 17 Sep 2006 16:49:49 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH] GFP_THISNODE for the slab allocator In-Reply-To: <20060917152723.5bb69b82.pj@sgi.com> Message-ID: References: <20060914220011.2be9100a.akpm@osdl.org> <20060914234926.9b58fd77.pj@sgi.com> <20060915002325.bffe27d1.akpm@osdl.org> <20060915004402.88d462ff.pj@sgi.com> <20060915010622.0e3539d2.akpm@osdl.org> <20060917041707.28171868.pj@sgi.com> <20060917060358.ac16babf.pj@sgi.com> <20060917152723.5bb69b82.pj@sgi.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Paul Jackson Cc: clameter@sgi.com, akpm@osdl.org, linux-mm@kvack.org, rientjes@google.com List-ID: On Sun, 17 Sep 2006, Paul Jackson wrote: > David, > > Could you run the following on your fake numa booted box, and > report the results: > > find /sys/devices -name distance | xargs head > With NUMA emulation, the distance from a node to itself is 10 and the distance to all other fake nodes is 20. So for numa=fake=4, root@numa:/$ cat /sys/devices/system/node/node*/distance 10 20 20 20 20 10 20 20 20 20 10 20 20 20 20 10 > You've been looking at this fake NUMA code recently, David. > > Perhaps you can recommend some other way from within the > mm/page_alloc.c code to efficiently (just a couple cache lines) > answer the question: > > Given two node numbers, are they really just two fake nodes > on the same hardware node, or are they really on two distinct > hardware nodes? > The cpumap for all fake nodes are always 00000000 except for node0 which reports the true hardware configuration. Using the previous example, root@numa:/$ cat /sys/devices/system/node/node*/cpumap 00000003 00000000 00000000 00000000 (Note: 00000003 because numa.* is a dual-core machine). David -- 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