Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753237Ab2JMJyx (ORCPT ); Sat, 13 Oct 2012 05:54:53 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:47650 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751960Ab2JMJyv (ORCPT ); Sat, 13 Oct 2012 05:54:51 -0400 Date: Sat, 13 Oct 2012 02:54:49 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Ezequiel Garcia cc: Andi Kleen , Linux Kernel Mailing List , linux-mm@kvack.org, Tim Bird , celinux-dev@lists.celinuxforum.org Subject: Re: [Q] Default SLAB allocator In-Reply-To: Message-ID: References: User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1278 Lines: 37 On Fri, 12 Oct 2012, Ezequiel Garcia wrote: > >> SLUB is a non-starter for us and incurs a >10% performance degradation in > >> netperf TCP_RR. > > > > Where are you seeing that? > In my benchmarking results. > Notice that many defconfigs are for embedded devices, > and many of them say "use SLAB"; I wonder if that's right. > If a device doesn't require the smallest memory footprint possible (SLOB) then SLAB is the right choice when there's a limited amount of memory; SLUB requires higher order pages for the best performance (on my desktop system running with CONFIG_SLUB, over 50% of the slab caches default to be high order). > Is there any intention to replace SLAB by SLUB? There may be an intent, but it'll be nacked as long as there's a performance degradation. > In that case it could make sense to change defconfigs, although > it wouldn't be based on any actual tests. > Um, you can't just go changing defconfigs without doing some due diligence in ensuring it won't be deterimental for those users. -- 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/