From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fed1rmmtao03.cox.net (fed1rmmtao03.cox.net [68.230.241.36]) by ozlabs.org (Postfix) with ESMTP id B471867C1B for ; Mon, 4 Jul 2005 04:32:39 +1000 (EST) Date: Sun, 3 Jul 2005 11:32:37 -0700 From: Tom Rini To: Olaf Hering Message-ID: <20050703183237.GC16764@smtp.west.cox.net> References: <17016.29775.224816.691409@cargo.ozlabs.ibm.com> <20050703172955.GA25976@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20050703172955.GA25976@suse.de> Cc: linuxppc-dev@ozlabs.org Subject: Re: [PATCH] Set cpu explicitly in kernel compiles List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sun, Jul 03, 2005 at 07:29:55PM +0200, Olaf Hering wrote: > On Wed, May 04, Paul Mackeras wrote: > > > What do people think of this patch? The motivation for it is that a > > biarch gcc-4.0 will by default tune for POWER4, even for a 32-bit > > compile, meaning that we end up with a lot of nops we don't need. > > This also takes out -mstring. > > > > With this, the text size reduces by about 120k for my normal config > > when compiling with a biarch gcc-4.0. The text size also reduces > > slightly when compiling with the Debian gcc-3.3.5 (32-bit only, not > > biarch). > > > > If there are no objections I'll send this to Andrew and Linus. > > What will be done about this patch? -mcpu=750 reduces .text by 70k. The fix for the real problem is now in. Perhaps, based off gcc's info page, we should update (from what 2.6.12 looks like) to do: cpu-as-y = -Wa,-mcpu=powerpc # Pure ppc32 cpu-as-$(CONFIG_6xx) += -Wa,-maltivec cpu-as-$(CONFIG_PPC_601) := -Wa,-mcpu=601 # Or whatever the 601 option is cpu-as-$(CONFIG_PPC64BRIDGE) := -Wa,mcpu=powerpc64 < add 4xx/BookE here > And see what we get. I really don't think we should fall into the i386 ugly trap of i386/i486/i586/i586tsc/... 20 other options ..., esp since it looks like the main win is switching from 100% generic powerpc to something more specific. And going with the generic name means if gcc starts doing something different on 750 vs 7400 vs 604, we win. -- Tom Rini http://gate.crashing.org/~trini/