From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philip Craig Subject: Re: [PATCH] libxtables: Dont initialize global xt_params Date: Mon, 16 Feb 2009 14:51:58 +1000 Message-ID: <4998F0EE.3020404@snapgear.com> References: <1234448162.3271.1.camel@dogo.mojatatu.com> <200902121609.43664.thomas.jarosch@intra2net.com> <200902121641.54430.thomas.jarosch@intra2net.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Jan Engelhardt , hadi@cyberus.ca, Patrick McHardy , Pablo Neira Ayuso , netfilter-devel@vger.kernel.org To: Thomas Jarosch Return-path: Received: from rex.securecomputing.com ([203.24.151.4]:54200 "EHLO cyberguard.com.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756010AbZBPEwA (ORCPT ); Sun, 15 Feb 2009 23:52:00 -0500 In-Reply-To: <200902121641.54430.thomas.jarosch@intra2net.com> Sender: netfilter-devel-owner@vger.kernel.org List-ID: Thomas Jarosch wrote: > Well, I guess that's a job for the compiler/optimizer. I did a quick test by > writing two versions of a small program initializing a static variable with > zero and one version that doesn't (=zeroed in .bss). Guess what, > the size of the resulting executable stays the same. > > When I initialize the variable with a non-zero value, then the program size > increases. I tested "-O2", "-O0" and "-Os" and the results where the same. > Feel free to look at the assembler output, though I guess this optimization > is not measurable and makes the code harder to read :o) For gcc, this depends on the -fno-zero-initialized-in-bss option. Recommendations to avoid zero initialization generally come from a time when gcc didn't do this by default. Now it is more just personal preference.