From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753845AbaHSSyN (ORCPT ); Tue, 19 Aug 2014 14:54:13 -0400 Received: from fr1.as29.net ([62.210.131.231]:38390 "EHLO toothrot.meleeweb.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753804AbaHSSyL (ORCPT ); Tue, 19 Aug 2014 14:54:11 -0400 Date: Tue, 19 Aug 2014 20:54:02 +0200 From: Bertrand Jacquin To: Rusty Russell Cc: Andi Kleen , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, Willy Tarreau Subject: Re: [PATCH 2/3] kbuild: handle module compression while running 'make modules_install'. Message-ID: <20140819185402.GA10263@lemonhead.scabb> References: <1408215016-1848-1-git-send-email-beber@meleeweb.net> <1408215016-1848-3-git-send-email-beber@meleeweb.net> <87lhqkmxdl.fsf@tassilo.jf.intel.com> <87iolojrdq.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87iolojrdq.fsf@rustcorp.com.au> Jabber-ID: beber@meleeweb.net X-GPG-Key: 0x39BB8CF4 X-GPG-DirectLink: https://www.cacert.org/gpg.php?id=3&cert=14964 X-GPG-Fingerprint: 2CBD 6A23 D980 3E32 66D1 573D 89B8 C953 39BB 8CF4 X-Pants: Off User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, D'ar meurzh 19 a viz Eost 2014 e 19 eur 55, « Rusty Russell » he deus skrivet : > Andi Kleen writes: > > Bertrand Jacquin writes: > >> > >> +# CONFIG_MODULE_COMPRESS, if defined, will cause module to be compressed > >> +# after they are installed in agreement with CONFIG_MODULE_COMPRESS_GZIP > >> +# or CONFIG_MODULE_COMPRESS_XZ. > >> + > >> +mod_compress_cmd = true > >> +ifdef CONFIG_MODULE_COMPRESS > >> + ifdef CONFIG_MODULE_COMPRESS_GZIP > >> + mod_compress_cmd = gzip -n -9 > > > > Please don't use gzip -9. The gain is very small, but it can make > > the time to compress much longer. Just use plain gzip. > > Interesting: > > $ time find * -name '*.ko' | xargs -n 1 gzip > real 0m9.404s > user 0m7.283s > sys 0m1.667s > $ du -c `find * -name '*.ko.gz'` | tail -n1 > 56412 total > > time find * -name '*.ko' | xargs -n 1 gzip -9 > real 1m1.968s > user 0m58.850s > sys 0m1.786s > $ du -c `find * -name '*.ko.gz'` | tail -n1 > 55764 total > > $ time find * -name '*.ko' | xargs -n 1 xz > real 1m23.396s > user 1m13.893s > sys 0m9.134s > $ du -c `find * -name '*.ko.xz` | tail -n1 > 46868 total > > $ time find * -name '*.ko' | xargs -n 1 xz -9 > real 1m47.202s > user 1m25.962s > sys 0m21.298s > $ du -c `find * -name '*.ko.xz` | tail -n1 > 46868 total > > So, Andi is right. Please skip -9 for both options: it makes little > (.gz) or no (.xz) difference and it slows things down. Thank you Andi and Rusty for the feedback. I'm current updating patches to drop -9 usage. -- Beber