Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753100AbYLZXXg (ORCPT ); Fri, 26 Dec 2008 18:23:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752191AbYLZXX2 (ORCPT ); Fri, 26 Dec 2008 18:23:28 -0500 Received: from sovereign.computergmbh.de ([85.214.69.204]:54910 "EHLO sovereign.computergmbh.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751845AbYLZXX1 (ORCPT ); Fri, 26 Dec 2008 18:23:27 -0500 Date: Sat, 27 Dec 2008 00:23:24 +0100 (CET) From: Jan Engelhardt To: david@lang.hm cc: Roland , linux-kernel@vger.kernel.org, Sam Ravnborg Subject: Re: [PATCH] Compress kernel modules on installation In-Reply-To: Message-ID: References: <005401c96797$df055100$6602a8c0@bui.materna.com> User-Agent: Alpine 2.00 (LSU 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1867 Lines: 58 On Friday 2008-12-26 23:28, david@lang.hm wrote: >>>> ( see >>>> http://www.linuxjournal.com/files/linuxjournal.com/linuxjournal/articles/080/8051/8051f1.png >>>> ) >>> >>> this varies a lot on the particulars of the data being compressed. >> >> see my other reply. > > IIRC the default is 5 default is 6 (man gzip). > instead of doing the compression when doing the modules_install do it when they > are compiled (just like we do for the kernel itself). if you just spent the cpu > to build the thing, the cpu to compress it isn't much. I'd rather do the compression later on - or do you want to spend gzipping all day when doing `make foo.ko` as a developer? ;-) >> $ find . -iname "*.gz" | xargs du -cs -B 4096 | grep total >> 7086 total >> $ echo $[7086*4096] >> 29024256 >> $ echo $[29024256-24782942] >> 4241314 >> >> So that's like 4M going off for the block stuff. Given that >> the compression actually saved about 50 MB, I think we >> can live with the 4M - especially since they have been >> there already one way or another. > > if I'm reading the numbers correctly that's about 16% of the space taken by the > final result Assuming that the x in (filesize % 4096 == x) is randomly distributed over 0..4095 for gzip modules, I proclaim that it is similarly randomly distributed for noncompressed modules. As such, the overhead is always there and gzipping does not make it worse or better. So you always have the overhead. uncompressed: $ du as above 113360896 $ byte counted: 109270606 differnece: 4.09 MB You always pay that price for having single files. So I dismiss it from the discussion ;-) -- 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/