Return-Path: Received: from mout.web.de ([212.227.17.11]:57676 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751781AbdLCV5c (ORCPT ); Sun, 3 Dec 2017 16:57:32 -0500 Subject: Re: Difficulties for compilation without extra optimisation To: Steven Rostedt , kernel-janitors@vger.kernel.org Cc: linux-kselftest@vger.kernel.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Trond Myklebust References: <7f072f78-eef4-6d87-d233-cee71dac5a32@users.sourceforge.net> <1512314250.3673.6.camel@primarydata.com> <20171203162256.4ea0750d@vmware.local.home> From: SF Markus Elfring Message-ID: Date: Sun, 3 Dec 2017 22:56:51 +0100 MIME-Version: 1.0 In-Reply-To: <20171203162256.4ea0750d@vmware.local.home> Content-Type: text/plain; charset=utf-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: > Why would you compile the kernel without optimization? I would like to see how big an effect finally is in such a build configuration after specific source code adjustments. > There's many places in the kernel that WILL NOT BUILD without optimization. I did not really know this detail so far. I noticed that the optimised build variants worked during my test comparisons. > In fact, we do a lot of tricks to make sure that things work the way > we expect it to, because we add broken code that only gets compiled out > when gcc optimizes the code the way we expect it to be, > and the kernel build will break otherwise. Thanks for your information. Can the software areas distinguished where such special handling matters? Regards, Markus