Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759985AbYCCVbW (ORCPT ); Mon, 3 Mar 2008 16:31:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752276AbYCCVbA (ORCPT ); Mon, 3 Mar 2008 16:31:00 -0500 Received: from rv-out-0910.google.com ([209.85.198.185]:53941 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751492AbYCCVa7 (ORCPT ); Mon, 3 Mar 2008 16:30:59 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=wPwrULt0/1Fksms1x+pxgY0gfbBe7K+uTkBZF7NrQwsRvB1QdLKBxeHUYcH2BiSl3fcSqy7iJ4UIgxQnWSJGMhh4f/fgpc4Pv5+ZC/LicAFjFu8eqB5T+8CwrAEYbtd4BEgBuVtsqpPL7u8Ncm1WwjLDp1YLg75WItgli00V9kU= Message-ID: <84144f020803031330i2c0ea1f6kc5b02c8b26145797@mail.gmail.com> Date: Mon, 3 Mar 2008 23:30:56 +0200 From: "Pekka Enberg" To: "Christoph Lameter" Subject: Re: [rfc][patch 1/3] slub: fix small HWCACHE_ALIGN alignment Cc: "Nick Piggin" , netdev@vger.kernel.org, "Linux Kernel Mailing List" , yanmin_zhang@linux.intel.com, "David Miller" , "Eric Dumazet" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080303093449.GA15091@wotan.suse.de> <20080303200613.GC8974@wotan.suse.de> <20080303201701.GF8974@wotan.suse.de> X-Google-Sender-Auth: a1a1a051a721e480 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1017 Lines: 24 Hi, On Mon, 3 Mar 2008, Nick Piggin wrote: > > > HWCACHE_ALIGN means that you want the object to be aligned at > > > cacheline boundaries for optimization. Why does crossing cacheline > > > boundaries matter in this case? > > > > No, HWCACHE_ALIGN means that you want the object not to cross cacheline > > boundaries for at least cache_line_size() bytes. You invented new On Mon, Mar 3, 2008 at 11:16 PM, Christoph Lameter wrote: > Interesting new definition.... Well, not my definition either but SLAB has guaranteed that for small objects in the past, so I think Nick has a point here. However, with all this back and forth, I've lost track why this matters. I suppose it causes regression on some workload? 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/