Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754622AbXJLCEb (ORCPT ); Thu, 11 Oct 2007 22:04:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753923AbXJLCEW (ORCPT ); Thu, 11 Oct 2007 22:04:22 -0400 Received: from stout.engsoc.carleton.ca ([134.117.69.22]:40712 "EHLO stout.engsoc.carleton.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753874AbXJLCEW (ORCPT ); Thu, 11 Oct 2007 22:04:22 -0400 Date: Thu, 11 Oct 2007 22:04:19 -0400 From: Kyle McMartin To: Paul Mackerras Cc: Olof Johansson , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, lethal@linux-sh.org, kyle@parisc-linux.org, grundler@parisc-linux.org, linuxppc-dev@ozlabs.org Subject: Re: [PATCH 2/2] powerpc: Switch to generic WARN_ON()/BUG_ON() Message-ID: <20071012020419.GB19268@fattire.cabal.ca> References: <20071011171211.GB10877@lixom.net> <20071011171413.GC10877@lixom.net> <18190.52379.97647.468384@cargo.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <18190.52379.97647.468384@cargo.ozlabs.ibm.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 818 Lines: 21 On Fri, Oct 12, 2007 at 11:23:39AM +1000, Paul Mackerras wrote: > Olof Johansson writes: > > > Not using the ppc-specific WARN_ON/BUG_ON constructs actually saves about > > 4K text on a ppc64_defconfig. The main reason seems to be that prepping > > the arguments to the conditional trap instructions is more work than > > just doing a compare and branch. > > It might be more instructions but it takes fewer cycles, I would > expect. Do you have the actual instruction sequences to compare? > I really hope WARN_ON/BUG_ON aren't hotpaths on powerpc. ;-) Cheers, Kyle - 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/