From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753646AbeDVUwO (ORCPT ); Sun, 22 Apr 2018 16:52:14 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:45747 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753537AbeDVUwK (ORCPT ); Sun, 22 Apr 2018 16:52:10 -0400 Date: Sun, 22 Apr 2018 22:52:08 +0200 From: Pavel Machek To: Paul Menzel Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Ingo Molnar Subject: Re: How to disable Linux =?utf-8?Q?kernel_?= =?utf-8?Q?self-extraction_=28KERNEL=5FGZIP=2C_KERNEL=5FBZIP2=2C_=E2=80=A6?= =?utf-8?B?KT8=?= Message-ID: <20180422205208.GA8672@amd> References: <9468be0e-5eb9-246c-e60e-3d8019a42fd1@molgen.mpg.de> <20180422102033.GB26243@amd> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="wRRV7LY7NUeQGEoC" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --wRRV7LY7NUeQGEoC Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > >>I try to decrease boot time, and my system has an SSD and enough space,= so > >>loading 18 instead of 12 MB doesn=E2=80=99t make a difference, but the > >>self-extraction is noticeable. So, I like to disable it. > > > >How long does GZIP extraction take on your hardware? >=20 > It=E2=80=99s hard to measure =E2=80=93 at least I didn=E2=80=99t find a w= ay to do so =E2=80=93, but counting > from the last GRUB message to the first message of Linux (with `quiet` > removed from the the command line), it takes roughly *two* seconds. >=20 > ``` > $ ls -l /boot/vmlinuz-4.15.0-3-686-pae > -rw-r--r-- 1 root root 3987200 Apr 19 12:13 /boot/vmlinuz-4.15.0-3-686-p= ae > $ ls -lh /boot/vmlinuz-4.15.0-3-686-pae > -rw-r--r-- 1 root root 3,9M Apr 19 12:13 /boot/vmlinuz-4.15.0-3-686-pae > $ time scripts/extract-vmlinux vmlinuz-4.15.0-3-686-pae > bla.txt >=20 > real 0m1,204s > user 0m1,041s > sys 0m0,245s > ``` Interesting; looks like I have faster machine (thinkpad X220). pavel@duo:/data/l/linux$ time scripts/extract-vmlinux /tmp/vmlinux.bin > /tmp/delme 0.21user 0.15system 0.66 (0m0.660s) elapsed 56.36%CPU pavel@duo:/data/l/linux$ ls -al /tmp/delme -rw-r--r-- 1 pavel pavel 18275356 Apr 22 22:44 /tmp/delme pavel@duo:/data/l/linux$ gzip /tmp/delme pavel@duo:/data/l/linux$ time gzip -d /tmp/delme.gz 0.21user 0.02system 0.23 (0m0.232s) elapsed 100.03%CPU pavel@duo:/data/l/linux$ gzip -1 /tmp/delme pavel@duo:/data/l/linux$ time gzip -d /tmp/delme.gz 0.22user 0.03system 0.25 (0m0.257s) elapsed 100.11%CPU pavel@duo:/data/l/linux$ time gzip -d /tmp/delme.gz =2E.and it also looks like extract-kernel is significantly slower than gzip -9, because it is not using all the CPU. Strange. Interesting. I somehow assumed gzip -d would be faster than that on modern machines. So yes, looks like uncompressed kernel image may be good idea. Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --wRRV7LY7NUeQGEoC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlrc9fgACgkQMOfwapXb+vIQMACfWKL7S7CGpnJHs0CZePLCUqx1 XtQAoKIsOW38Rxqj0S7UFG5FBrEGHQux =sfCt -----END PGP SIGNATURE----- --wRRV7LY7NUeQGEoC--