From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751382AbeEBJfA (ORCPT ); Wed, 2 May 2018 05:35:00 -0400 Received: from mga07.intel.com ([134.134.136.100]:16513 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750883AbeEBJe6 (ORCPT ); Wed, 2 May 2018 05:34:58 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,354,1520924400"; d="scan'208";a="220974886" Date: Wed, 2 May 2018 17:24:58 +0800 From: "Du, Changbin" To: Randy Dunlap Cc: changbin.du@intel.com, yamada.masahiro@socionext.com, michal.lkml@markovi.net, tglx@linutronix.de, mingo@redhat.com, akpm@linux-foundation.org, x86@kernel.org, lgirdwood@gmail.com, broonie@kernel.org, arnd@arndb.de, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Subject: Re: [PATCH 4/5] kernel hacking: new config DEBUG_EXPERIENCE to apply GCC -Og optimization Message-ID: <20180502092458.zss44oqy7fqsyszp@intel.com> References: <1525179614-14571-1-git-send-email-changbin.du@intel.com> <1525179614-14571-5-git-send-email-changbin.du@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180323-6-5ca392 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 01, 2018 at 08:25:27AM -0700, Randy Dunlap wrote: > Good morning. > > On 05/01/2018 06:00 AM, changbin.du@intel.com wrote: > > From: Changbin Du > > > > > > Signed-off-by: Changbin Du > > --- > > Makefile | 4 ++++ > > include/linux/compiler-gcc.h | 2 +- > > include/linux/compiler.h | 2 +- > > lib/Kconfig.debug | 21 +++++++++++++++++++++ > > 4 files changed, 27 insertions(+), 2 deletions(-) > > > > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index 90f35ad..2432e77d 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -211,6 +211,27 @@ config NO_AUTO_INLINE > > > > Use only if you want to debug the kernel. > > > > +config DEBUG_EXPERIENCE > > + bool "Optimize for better debugging experience (-Og)" > > + default n > > + select NO_AUTO_INLINE > > + depends on !CC_OPTIMIZE_FOR_SIZE > > + help > > + This will apply GCC '-Og' optimization level get supported from > > which is supported since > > > + GCC 4.8. This optimization level offers a reasonable level of > > + optimization while maintaining fast compilation and a good > > + debugging experience. It is similar to '-O1' while perfer keeping > > while preferring to keep > > > + debug ability over runtime speed. The overall performance will > > + drop a bit. > > + > > + If enabling this option break your kernel, you should either > > breaks > > > + disable this or find a fix (mostly in the arch code). Currently > > + this option has only be tested in qemu x86_64 guest. > > + > > + Use only if you want to debug the kernel, especially if you want > > + to have better kernel debugging experience with gdb facilities > > + like kgdb and qemu. > > + > > config ENABLE_WARN_DEPRECATED > > bool "Enable __deprecated logic" > > default y > > > > thanks, > -- > ~Randy Thanks for your correction, I will update. -- Thanks, Changbin Du