From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 115496B0047 for ; Sat, 4 Sep 2010 04:00:28 -0400 (EDT) Date: Sat, 4 Sep 2010 17:58:40 +1000 From: Dave Chinner Subject: Re: [PATCH 3/3] mm: page allocator: Drain per-cpu lists after direct reclaim allocation fails Message-ID: <20100904075840.GE705@dastard> References: <1283504926-2120-1-git-send-email-mel@csn.ul.ie> <1283504926-2120-4-git-send-email-mel@csn.ul.ie> <20100903160026.564fdcc9.akpm@linux-foundation.org> <20100904022545.GD705@dastard> <20100903202101.f937b0bb.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100903202101.f937b0bb.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: Mel Gorman , Linux Kernel List , linux-mm@kvack.org, Rik van Riel , Johannes Weiner , Minchan Kim , Christoph Lameter , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Wu Fengguang , David Rientjes List-ID: On Fri, Sep 03, 2010 at 08:21:01PM -0700, Andrew Morton wrote: > On Sat, 4 Sep 2010 12:25:45 +1000 Dave Chinner wrote: > > > Still, given the improvements in performance from this patchset, > > I'd say inclusion is a no-braniner.... > > OK, thanks. > > It'd be interesting to check the IPI frequency with and without - > /proc/interrupts "CAL" field. Presumably it went down a lot. Maybe I suspected you would ask for this. I happened to dump /proc/interrupts after the livelock run finished, so you're in luck :) The lines below are: before: before running the single 50M inode create workload after: the numbers after the run completes livelock: the numbers after two runs with a livelock in the second Vanilla 2.6.36-rc3: before: 561 350 614 282 559 335 365 363 after: 10472 10473 10544 10681 9818 10837 10187 9923 .36-rc3 With patchset: before: 452 426 441 337 748 321 498 357 after: 9463 9112 8671 8830 9391 8684 9768 8971 The numbers aren't that different - roughly 10% lower on average with the patchset. I will state that vanilla kernel runs I ijust did had noticably more consistent performance than the previous results I had acheived, so perhaps it wasn't triggering the livelock conditions as effectively this time through. And finally: livelock: 59458 58367 58559 59493 59614 57970 59060 58207 So the livelock case tends to indicate roughly 40,000 more IPI interrupts per CPU occurred. The livelock occurred for close to 5 minutes, so that's roughly 130 IPIs per second per CPU.... Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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