From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753502AbeDVTz4 (ORCPT ); Sun, 22 Apr 2018 15:55:56 -0400 Received: from mx3.molgen.mpg.de ([141.14.17.11]:45967 "EHLO mx1.molgen.mpg.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753417AbeDVTzz (ORCPT ); Sun, 22 Apr 2018 15:55:55 -0400 Subject: =?UTF-8?Q?Re:_How_to_disable_Linux_kernel_self-extraction_=28KERNEL?= =?UTF-8?B?X0daSVAsIEtFUk5FTF9CWklQMiwg4oCmKT8=?= To: Pavel Machek Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Ingo Molnar References: <9468be0e-5eb9-246c-e60e-3d8019a42fd1@molgen.mpg.de> <20180422102033.GB26243@amd> From: Paul Menzel Message-ID: Date: Sun, 22 Apr 2018 21:55:51 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180422102033.GB26243@amd> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dear Pavel, Am 22.04.2018 um 12:20 schrieb Pavel Machek: > On Fri 2018-04-20 16:36:00, Paul Menzel wrote: >> I try to decrease boot time, and my system has an SSD and enough space, so >> loading 18 instead of 12 MB doesn’t make a difference, but the >> self-extraction is noticeable. So, I like to disable it. > > How long does GZIP extraction take on your hardware? It’s hard to measure – at least I didn’t find a way to do so –, 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. ``` $ 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-pae $ 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 real 0m1,204s user 0m1,041s sys 0m0,245s ``` As another data point, my self-built (*bigger*) image with XZ used for compression. ``` $ ls -lh /boot/vmlinuz-4.16.0+ -rw-r--r-- 1 root root 6,1M Apr 14 10:48 /boot/vmlinuz-4.16.0+ $ time /usr/src/linux-headers-4.17.0-rc1+/scripts/extract-vmlinux vmlinuz-4.16.0+ > bla.txt real 0m2,190s user 0m1,792s sys 0m0,500s ``` So, it’s really noticeable if the rest of the system starts in less then five seconds to a login prompt, or you are trying to achieve to display the LUKS passphrase dialog more or less instantly. Kind regards, Paul