From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:29839 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729184AbfDDUTD (ORCPT ); Thu, 4 Apr 2019 16:19:03 -0400 Date: Thu, 4 Apr 2019 15:18:55 -0500 From: Josh Poimboeuf Subject: Re: [PATCH v2] kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled Message-ID: <20190404201855.xtvtgxaaomcmowrt@treble> References: <20190404184411.1392-1-mbenes@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190404184411.1392-1-mbenes@suse.cz> Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Miroslav Benes Cc: yamada.masahiro@socionext.com, michal.lkml@markovi.net, pmladek@suse.com, jikos@kernel.org, joe.lawrence@redhat.com, ggherdovich@suse.cz, linux-kbuild@vger.kernel.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org On Thu, Apr 04, 2019 at 08:44:11PM +0200, Miroslav Benes wrote: > GCC 9 introduces a new option, -flive-patching. It disables certain > optimizations which could make a compilation unsafe for later live > patching of the running kernel. > > The option is used only if CONFIG_LIVEPATCH is enabled and $(CC) > supports it. > > Performance impact of the option was measured on three different > Intel machines - two bigger NUMA boxes and one smaller UMA box. Kernel > intensive (IO, scheduling, networking) benchmarks were selected, plus a > set of HPC workloads from NAS Parallel Benchmark. The tests were done on > upstream kernel 5.0-rc8 with openSUSE Leap 15.0 userspace. > > The majority of the tests is unaffected. The only significant exception > is the scheduler section which suffers 1-3% degradation. > > Evaluated-by: Giovanni Gherdovich > Signed-off-by: Miroslav Benes > --- > The patch is based on master branch of the livepatching tree on > git.kernel.org. > > Many thanks to Giovanni who ran the whole testing campaign and analyzed > the results. I archived the dashboard and detailed data. If anyone is > interested, we could probably set up a public website somewhere. Acked-by: Josh Poimboeuf While we're on the subject, I'm glad to see ongoing activity on klp-convert (though I haven't had a chance to follow the discussions). What's the status of the rest of the needed bits? - kgraft-analysis-tool - will this also be submitted for inclusion in the kernel tree? - Documentation about how to create a patch - The other bits I think Nicolai has been working on to eliminate all the manual steps -- Josh