From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by nf-out-0910.google.com with SMTP id h3so1058893nfh for ; Mon, 12 Nov 2007 20:27:35 -0800 (PST) Message-ID: <2c0942db0711122027m5b11502cveded5705c0bc4f64@mail.gmail.com> Date: Mon, 12 Nov 2007 20:27:34 -0800 From: "Ray Lee" Subject: Re: x86_64: Make sparsemem/vmemmap the default memory model In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200711130059.34346.ak@suse.de> <200711130149.54852.ak@suse.de> Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman , Andi Kleen , Andy Whitcroft List-ID: On Nov 12, 2007 7:42 PM, Christoph Lameter wrote: > Ok here is the patch to remove DISCONTIG and FLATMEM > > x86_64: Make sparsemem/vmemmap the default memory model > > Use sparsemem as the only memory model for UP, SMP and NUMA. > Measurements indicate that DISCONTIGMEM has a higher overhead > than sparsemem. And FLATMEMs benefits are minimal. So I think its > best to simply standardize on sparsemem. > > Results of page allocator tests (test can be had via git from slab git > tree branch tests) > > Measurements in cycle counts. 1000 allocations were performed and then the > average cycle count was calculated. > > Order FlatMem Discontig SparseMem > 0 639 665 641 > 1 567 647 593 > 2 679 774 692 > 3 763 967 781 > 4 961 1501 962 > 5 1356 2344 1392 > 6 2224 3982 2336 > 7 4869 7225 5074 > 8 12500 14048 12732 > 9 27926 28223 28165 > 10 58578 58714 58682 Discontig obviously needs to die. However, FlatMem is consistently faster, averaging about 2.1% better overall for your numbers above. Is the page allocator not, erm, a fast path, where that matters? Order Flat Sparse % diff 0 639 641 0.3 1 567 593 4.4 2 679 692 1.9 3 763 781 2.3 4 961 962 0.1 5 1356 1392 2.6 6 2224 2336 4.8 7 4869 5074 4.0 8 12500 12732 1.8 9 27926 28165 0.8 10 58578 58682 0.2 -- 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