Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756966AbZAVKBj (ORCPT ); Thu, 22 Jan 2009 05:01:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755164AbZAVKB2 (ORCPT ); Thu, 22 Jan 2009 05:01:28 -0500 Received: from mail-ew0-f20.google.com ([209.85.219.20]:41732 "EHLO mail-ew0-f20.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754534AbZAVKB1 (ORCPT ); Thu, 22 Jan 2009 05:01:27 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=fzepBKyHxpqAmURD5OD0+yg4UulS3Es/D45KwaPy4VdMSEVt6ThUqRsmMy3m/NW51M peklbiLMGtZsx9jG0YBJjotXiuDq+5fov6VEiOTPszCnVq/Eb6AwmTmTBAkvbhbjEdpt WJtOADG/t5LnTaNBh7kH1pW2QIEesOcCcra3Y= MIME-Version: 1.0 In-Reply-To: References: <20090121143008.GV24891@wotan.suse.de> Date: Thu, 22 Jan 2009 12:01:24 +0200 X-Google-Sender-Auth: fec1038159e3581f Message-ID: <84144f020901220201g6bdc2d5maf3395fc8b21fe67@mail.gmail.com> Subject: Re: [patch] SLQB slab allocator From: Pekka Enberg To: Hugh Dickins Cc: Nick Piggin , Linux Memory Management List , Linux Kernel Mailing List , Andrew Morton , Lin Ming , "Zhang, Yanmin" , Christoph Lameter Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1541 Lines: 29 Hi Hugh, On Wed, Jan 21, 2009 at 8:10 PM, Hugh Dickins wrote: > I was initially _very_ impressed by how well it did on my venerable > tmpfs loop swapping loads, where I'd expected next to no effect; but > that turned out to be because on three machines I'd been using SLUB, > without remembering how default slub_max_order got raised from 1 to 3 > in 2.6.26 (hmm, and Documentation/vm/slub.txt not updated). > > That's been making SLUB behave pretty badly (e.g. elapsed time 30% > more than SLAB) with swapping loads on most of my machines. Though > oddly one seems immune, and another takes four times as long: guess > it depends on how close to thrashing, but probably more to investigate > there. I think my original SLUB versus SLAB comparisons were done on > the immune one: as I remember, SLUB and SLAB were equivalent on those > loads when SLUB came in, but even with boot option slub_max_order=1, > SLUB is still slower than SLAB on such tests (e.g. 2% slower). > FWIW - swapping loads are not what anybody should tune for. What kind of machine are you seeing this on? It sounds like it could be a side-effect from commit 9b2cd506e5f2117f94c28a0040bf5da058105316 ("slub: Calculate min_objects based on number of processors"). Pekka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/