Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759268Ab0FJO22 (ORCPT ); Thu, 10 Jun 2010 10:28:28 -0400 Received: from one.firstfloor.org ([213.235.205.2]:48181 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753400Ab0FJO21 (ORCPT ); Thu, 10 Jun 2010 10:28:27 -0400 Date: Thu, 10 Jun 2010 16:28:25 +0200 From: Andi Kleen To: Peter Zijlstra Cc: Andi Kleen , Ingo Molnar , Jason Baron , linux-kernel@vger.kernel.org, mathieu.desnoyers@polymtl.ca, hpa@zytor.com, tglx@linutronix.de, rostedt@goodmis.org, roland@redhat.com, rth@redhat.com, mhiramat@redhat.com, fweisbec@gmail.com, avi@redhat.com, davem@davemloft.net, vgoyal@redhat.com, sam@ravnborg.org Subject: Re: [PATCH 03/13] jump label v9: x86 support Message-ID: <20100610142825.GB19561@basil.fritz.box> References: <1276171930.2077.200.camel@twins> <20100610121440.GA20130@elte.hu> <20100610132616.GA19561@basil.fritz.box> <1276179131.2077.348.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1276179131.2077.348.camel@twins> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1162 Lines: 32 On Thu, Jun 10, 2010 at 04:12:11PM +0200, Peter Zijlstra wrote: > On Thu, 2010-06-10 at 15:26 +0200, Andi Kleen wrote: > > The code generated by -Os is often terrible. > > Is anybody on the gcc side of things looking into curing that? The problem is that the smallest code is often terrible. You could often be much better with spending a few more bytes. But -Os means "smallest" On the other hand -Os could be likely made smaller (it often still is not very good), but I fear that would make things even worse. We probably would need a -Osmall-but-not-terrible or so, but that's not there. > > I mean, what's the point of having an -Os if its useless in practise. I think __hot / __cold but keeping the default at -O2 is a better approach anyways. Hot paths should be -O2. It just needs some more work. It already works for __init/__exit at least. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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/