From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-f66.google.com ([209.85.167.66]:38412 "EHLO mail-lf1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728679AbgFDNzH (ORCPT ); Thu, 4 Jun 2020 09:55:07 -0400 Received: by mail-lf1-f66.google.com with SMTP id 202so3657918lfe.5 for ; Thu, 04 Jun 2020 06:55:06 -0700 (PDT) Reply-To: efremov@linux.com References: From: Denis Efremov Subject: Re: [PATCH] kbuild: add variables for compression tools Message-ID: <635d02d6-05a9-7620-c386-dac766cd49da@linux.com> Date: Thu, 4 Jun 2020 16:55:03 +0300 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: sedat.dilek@gmail.com Cc: linux-kbuild@vger.kernel.org, Masahiro Yamada Hi, On 6/4/20 4:05 PM, Sedat Dilek wrote: > Hi Denis, > > is it possible to add ZSTD compression support with the possibility to > add - for example multithreading - options? Where do you want to use zstd in kernel? For example, to compress headers xz is used, to compress /proc/config.gz gzip is used. It could be relatively easy patched to use zstd for it and it could be easy to add tarzstd-pkg target for building the kernel as a zstd compressed tarball. However, I doubt that someone really needs it. xz is best for headers because of compression ratio, gzip is best for config because gzip is installed by default on most systems. To compress modules, ramdisk or kernel image with zstd one needs to implement zstd decompression algorithm in kernel. Given that there are already gzip,bzip2,lzma,xz,lzo,lz4 I really doubt that it will be useful. There should be a good comparison showing that kernel image with zstd, for example, beats gzip and couple of others in comression ratio and decompression speed to properly position the zstd algo. > For the documentation - which I have not checked - are the tools and > libs mentioned you will need to have installed for certain compression > tools? gzip, bzip2 are already installed on most systems. It's highly likely that lzo, lzma, xz will require you to install them. Thanks, Denis