From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx182.postini.com [74.125.245.182]) by kanga.kvack.org (Postfix) with SMTP id 69A566B006C for ; Tue, 20 Nov 2012 11:52:46 -0500 (EST) Received: by mail-bk0-f41.google.com with SMTP id jg9so2977440bkc.14 for ; Tue, 20 Nov 2012 08:52:44 -0800 (PST) Date: Tue, 20 Nov 2012 17:52:39 +0100 From: Ingo Molnar Subject: Re: [PATCH, v2] mm, numa: Turn 4K pte NUMA faults into effective hugepage ones Message-ID: <20121120165239.GA18345@gmail.com> References: <1353291284-2998-1-git-send-email-mingo@kernel.org> <20121119162909.GL8218@suse.de> <20121119191339.GA11701@gmail.com> <20121119211804.GM8218@suse.de> <20121119223604.GA13470@gmail.com> <20121120071704.GA14199@gmail.com> <20121120152933.GA17996@gmail.com> <20121120160918.GA18167@gmail.com> <50ABB06A.9000402@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50ABB06A.9000402@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Rik van Riel Cc: Linus Torvalds , David Rientjes , Mel Gorman , Linux Kernel Mailing List , linux-mm , Peter Zijlstra , Paul Turner , Lee Schermerhorn , Christoph Lameter , Andrew Morton , Andrea Arcangeli , Thomas Gleixner , Johannes Weiner , Hugh Dickins * Rik van Riel wrote: > Performance measurements will show us how much of an impact it > makes, since I don't think we have never done apples to apples > comparisons with just this thing toggled :) I've done a couple of quick measurements to characterise it: as expected this patch simply does not matter much when THP is enabled - and most testers I worked with had THP enabled. Testing with THP off hurst most NUMA workloads dearly and tells very little about the real NUMA story of these workloads. If you turn off THP you are living with a constant ~25% regression - just check the THP and no-THP numbers I posted: [ 32-warehouse SPECjbb test benchmarks ] mainline: 395 k/sec mainline +THP: 524 k/sec numa/core +patch: 512 k/sec [ +29.6% ] numa/core +patch +THP: 654 k/sec [ +24.8% ] The group of testers who had THP disabled was thus very low - maybe only Mel alone? The testers I worked with all had THP enabled. I'd encourage everyone to report unusual 'tweaks' done before tests are reported - no matter how well intended the purpose of that tweak. There's just so many config variations we can test and we obviously check the most logically and most scalably configured system variants first. Thanks, 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