Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757921Ab0BMTaK (ORCPT ); Sat, 13 Feb 2010 14:30:10 -0500 Received: from xenotime.net ([72.52.64.118]:39289 "HELO xenotime.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751228Ab0BMTaI (ORCPT ); Sat, 13 Feb 2010 14:30:08 -0500 Message-ID: <4B76FDBF.8050902@xenotime.net> Date: Sat, 13 Feb 2010 11:30:07 -0800 From: Randy Dunlap Organization: YPO4 User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091209 Fedora/3.0-3.fc11 Thunderbird/3.0 MIME-Version: 1.0 To: Geert Uytterhoeven CC: Jean Delvare , Pavel Machek , "J.H." , "FTPAdmin Kernel.org" , users@kernel.org, lasse.collin@tukaani.org, linux-kernel , mirrors@kernel.org Subject: Re: [kernel.org users] XZ Migration discussion References: <4B744E13.8040004@kernel.org> <20100211205129.GA26105@elf.ucw.cz> <20100213181008.479509f5@hyperion.delvare> <10f740e81002131049o196380a6tf863b7713e5aafc5@mail.gmail.com> In-Reply-To: <10f740e81002131049o196380a6tf863b7713e5aafc5@mail.gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3566 Lines: 85 On 02/13/10 10:49, Geert Uytterhoeven wrote: > On Sat, Feb 13, 2010 at 18:10, Jean Delvare wrote: >> On Thu, 11 Feb 2010 21:51:29 +0100, Pavel Machek wrote: >>> I believe this is cleanest. gzip has performance advantages, (...) >> >> I have been investigating this issue and would like to share my >> findings as an additional data point for this discussion. >> >> For my testing, I have been using the slowest machine I still have >> available here: a Pentium 166 MMX, with 64 MB of memory and a slow hard >> disk drive. I've been writing down the duration of each task it took to >> boot kernel 2.6.27.45 on this machine. I did this for both .gz and .bz2 >> formats. >> >> Raw results are as follow (format=min:s): >> >> downloading linux-2.6.27.tar.bz2 5:01 >> downloading patch-2.6.27.45.bz2 0:02 >> unpacking linux-2.6.27.tar.bz2 7:28 >> applying patch-2.6.27.45.bz2 1:21 >> ---------------------------------------------- >> total for bz2 13:52 >> >> downloading linux-2.6.27.tar.gz 6:23 >> downloading patch-2.6.27.45.gz 0:02 >> unpacking linux-2.6.27.tar.gz 3:20 >> applying patch-2.6.27.45.gz 1:10 >> ---------------------------------------------- >> total for gz 10:55 >> >> So the gz option is unsurprisingly faster, setting up the source tree >> takes almost 3 minutes less (-21%). >> >> Then the (common) build and installation times: >> >> building 117:26 >> installing modules 0:12 >> ---------------------------------------------- >> total 117:38 >> >> This is a customized kernel, as small as I could do, with almost no >> features and the minimal set of drivers. As you can see, the build time >> is one order of magnitude greater than the tree setup time. Comparing >> the total times from download to install between bz2 and gz: >> >> bz2: 13:52 + 117:38 = 131:30 >> gz: 10:55 + 117:38 = 128:33 >> >> Compared to bz2, gz saves... 2% on the overall time. As a conclusion, I >> think we can plain discard the argument "I need .gz because my machine >> is slow" from now on. It simply doesn't hold. > > 166 MHz and 64 MB of RAM is still an order of magnitude more than some other > machines Linux is capable of running on. > > Of course we no longer build kernels on those machines natively, we > cross-compile > on much faster machines (and use git to fetch the kernel sources, FWIW ;-). > > BTW, who still downloads full kernel tarballs? From my experience, that's mostly > distro people who have scripts to build kernels from tarballs + a > bunch of patches? All of my daily build & boot testing downloads tarballs. They use full linux-x.y.z for "releases" (like 2.6.32) and they use patch-x.y.z.gz/bz2 for intermediate versions. I don't mind updating the scripts to use .xz tarballs, but I would really prefer to stick with tarballs instead of git trees. > I guess actual developers use git nowadays, even if they're stuck on > an old 2.6.x kernel? > Backporting critical fixes is sooo much easier using git cherry-pick... > > Do we have statistics about tarball downloads vs. git clone / git pull? That would be good to see. -- ~Randy -- 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/