From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752845AbZI1Typ (ORCPT ); Mon, 28 Sep 2009 15:54:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752397AbZI1Typ (ORCPT ); Mon, 28 Sep 2009 15:54:45 -0400 Received: from one.firstfloor.org ([213.235.205.2]:55429 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752286AbZI1Tyo (ORCPT ); Mon, 28 Sep 2009 15:54:44 -0400 Date: Mon, 28 Sep 2009 21:54:45 +0200 From: Andi Kleen To: Arjan van de Ven Cc: Andrew Morton , Andi Kleen , Mathieu Desnoyers , Ingo Molnar , linux-kernel@vger.kernel.org, Jason Baron , Rusty Russell , Adrian Bunk , Christoph Hellwig Subject: Re: [patch 02/12] Immediate Values - Architecture Independent Code Message-ID: <20090928195444.GF1656@one.firstfloor.org> References: <20090924132626.485545323@polymtl.ca> <20090924133359.218934235@polymtl.ca> <20090924212013.d27226c4.akpm@linux-foundation.org> <20090928012337.GC1656@one.firstfloor.org> <20090928104617.9c4b868a.akpm@linux-foundation.org> <20090928200317.64a419ff@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090928200317.64a419ff@infradead.org> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > btw just to add to this: > caches are unified code/data after L1 in general... it then does not > matter much if you encode the "almost constant" in the codestream or > slightly farther away, in both cases it takes up cache space. It does take up cache space, but when it's embedded in the instruction stream the CPU has it usually already prefetched (CPUs are very good at prefetching instructions). That's often not the case with arbitary data accesses like this. -Andi -- ak@linux.intel.com -- Speaking for myself only.