Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759206AbZAGUF0 (ORCPT ); Wed, 7 Jan 2009 15:05:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753171AbZAGUFJ (ORCPT ); Wed, 7 Jan 2009 15:05:09 -0500 Received: from pfepb.post.tele.dk ([195.41.46.236]:39656 "EHLO pfepb.post.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752600AbZAGUFI (ORCPT ); Wed, 7 Jan 2009 15:05:08 -0500 Date: Wed, 7 Jan 2009 21:06:46 +0100 From: Sam Ravnborg To: Jan Beulich Cc: ccache@lists.samba.org, Theodore Tso , linux-kernel@vger.kernel.org, Jan Engelhardt Subject: Re: [REGRESSION] Recent change to kernel spikes out ccache/distcc Message-ID: <20090107200646.GF4647@uranus.ravnborg.org> References: <496386EF.76E4.0078.0@novell.com> <20090106173300.GA10903@mit.edu> <49647B00.76E4.0078.0@novell.com> <20090107113138.GA29730@uranus.ravnborg.org> <4964AF8D.76E4.0078.0@novell.com> <20090107132337.GA2289@uranus.ravnborg.org> <4964C0A3.76E4.0078.0@novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4964C0A3.76E4.0078.0@novell.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2751 Lines: 73 On Wed, Jan 07, 2009 at 01:48:03PM +0000, Jan Beulich wrote: > >>> Sam Ravnborg 07.01.09 14:23 >>> > >On Wed, Jan 07, 2009 at 12:35:09PM +0000, Jan Beulich wrote: > >> >>> Sam Ravnborg 07.01.09 12:31 >>> > >> >What is the gain/pain ratio here? > >> > >> Certainly depends on the pov - it reduces the kernel module (disk) image > >> sizes quite a bit, so from a distro perspective its a move against the ever > >> growing package sizes (and the disk space) hundreds or even thousands > >> of modules require. > > > >The kernel modules seldom export anything so the benefit is minimal here. > > Not really, for highly modular distro kernels. > > >I did a 15 minutes hack to try ripping the .c -> .s -> .o stuff out. > > Looks good to me. In case you decide to revert the stuff for .29, I'll > merge this into my patch. As it stand now it: 1) breaks sparc32 build 2) causes regression with distcc/ccache use when MODVERSIONS are enabled 3) the concept is under discussion So I will have to revert it somehow. I will look into during a partial revert though as your patches had some stuff in them I like to keep or which does not harm (genksyms change for instance). > > >Jan - I need some hard numbers to convince me that stripping the > >__crc symbols is worth it. > > The on-disk size of the modules in my builds is reduced by about 5% with > this patch (but I can't immediately tell how much of this is due to __crc_* > vs. other symbol stripping). But if only on-disk size is your primary concern then another patch of Jan Engelhardt would be a bigger win: build: install modules compressed --- scripts/Makefile.modinst | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/scripts/Makefile.modinst b/scripts/Makefile.modinst index efa5d94..c3421a1 100644 --- a/scripts/Makefile.modinst +++ b/scripts/Makefile.modinst @@ -17,7 +17,7 @@ __modinst: $(modules) @: quiet_cmd_modules_install = INSTALL $@ - cmd_modules_install = mkdir -p $(2); cp $@ $(2) ; $(mod_strip_cmd) \ $(2)/$(notdir $@) + cmd_modules_install = mkdir -p $(2); cp $@ $(2) ; \ $(mod_strip_cmd) $(2)/$(notdir $@); gzip -9f $(2)/$(notdir $@) # Modules built outside the kernel source tree go into extra by default INSTALL_MOD_DIR ?= extra (cut'n'paste so will not apply direct) It does not decrease the size of vmlinux but the > 1000 modules are compressed. The patch will in some form be present in kbuild-next.git when I open up for that. Sam -- 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/