From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262340AbTFFW1Z (ORCPT ); Fri, 6 Jun 2003 18:27:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262362AbTFFW1Z (ORCPT ); Fri, 6 Jun 2003 18:27:25 -0400 Received: from wmail.atlantic.net ([209.208.0.84]:43418 "HELO wmail.atlantic.net") by vger.kernel.org with SMTP id S262340AbTFFW1Y (ORCPT ); Fri, 6 Jun 2003 18:27:24 -0400 Message-ID: <3EE11B41.80505@techsource.com> Date: Fri, 06 Jun 2003 18:52:49 -0400 From: Timothy Miller User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Linux Kernel Mailing List Subject: Results of actual compile printk format compression Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Just a quick note... Although my experiments with kernel printk format string compression have reported estimated shrinkage, this is the first time I have been able to compile a whole kernel with the compression filter. These results come from doing an allyesconfig of 2.5.68 and then weeding out anything that didn't build. One program extracts strings from preprocessor output, a second program determines how the strings will be encoded, and the third makes substitutions during a kernel compile. The uncompressed compile resulted in a kernel image of 24011892 bytes. The resulting image with format strings compressed is 23904708 bytes which is a shrinkage of 107184 bytes. Subtracting out an estimate of 3K for the dictionary and necessary modifications to printk, that results in a reduction of something like 104112 which is 4% of the original kernel size. That may not seem like a lot, but if you consider only the printk strings themselves, they are compressed to less than 50% of their original size (counting the dictionary but not printk code mods). So, I ask... is this a useful savings? Is there any chance anyone would bother to increase their compile time by a factor of 5 in order to shave off 4% or 100k bytes? (Not to mention that allyesconfig is a very unrealistic scenario.)