From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id B73296B01F5 for ; Sat, 10 Apr 2010 15:03:34 -0400 (EDT) Date: Sat, 10 Apr 2010 21:02:33 +0200 From: Ingo Molnar Subject: Re: [PATCH 00 of 41] Transparent Hugepage Support #17 Message-ID: <20100410190233.GA30882@elte.hu> References: <20100405232115.GM5825@random.random> <20100406011345.GT5825@random.random> <20100406090813.GA14098@elte.hu> <20100410184750.GJ5708@random.random> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100410184750.GJ5708@random.random> Sender: owner-linux-mm@kvack.org To: Andrea Arcangeli Cc: Linus Torvalds , Pekka Enberg , Andrew Morton , linux-mm@kvack.org, Marcelo Tosatti , Adam Litke , Avi Kivity , Izik Eidus , Hugh Dickins , Nick Piggin , Rik van Riel , Mel Gorman , Dave Hansen , Benjamin Herrenschmidt , Mike Travis , KAMEZAWA Hiroyuki , Christoph Lameter , Chris Wright , bpicco@redhat.com, KOSAKI Motohiro , Balbir Singh , Arnd Bergmann , "Michael S. Tsirkin" , Peter Zijlstra , Johannes Weiner , Daisuke Nishimura List-ID: * Andrea Arcangeli wrote: > [...] > > This is already fully usable and works great, and as Avi showed it boosts > even a sort on host by 6%, think about HPC applications, and soon I hope to > boost gcc on host by 6% (and of >15% in guest with NPT/EPT) by extending > vm_end in 2M chunks in glibc, at least for those huge gcc builds taking > >200M like translate.o of qemu-kvm... (so I hope soon gcc running on KVM > guest, thanks to EPT/NPT, will run faster than on mainline kernel without > transparent hugepages on bare metal). I think what would be needed is some non-virtualization speedup example of a 'non-special' workload, running on the native/host kernel. 'sort' is an interesting usecase - could it be patched to use hugepages if it has to sort through lots of data? Is it practical to run something like a plain make -jN kernel compile all in hugepages, and see a small but measurable speedup? Although it's not an ideal workload for computational speedups at all because a lot of the time we spend in a kernel build is really buildup/teardown of process state/context and similar 'administrative' overhead, while the true 'compilation work' is just a burst of a few dozen milliseconds and then we tear down all the state again. (It's very inefficient really.) Something like GIMP calculations would be a lot more representative of the speedup potential. Is it possible to run the GIMP with transparent hugepages enabled for it? Ingo -- 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