From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754081Ab2LEXIj (ORCPT ); Wed, 5 Dec 2012 18:08:39 -0500 Received: from mail.skyhub.de ([78.46.96.112]:36211 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752886Ab2LEXIi (ORCPT ); Wed, 5 Dec 2012 18:08:38 -0500 Date: Thu, 6 Dec 2012 00:08:35 +0100 From: Borislav Petkov To: John Cc: "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] Additional compiler optimization options Message-ID: <20121205230835.GF6222@liondog.tnic> Mail-Followup-To: Borislav Petkov , John , "linux-kernel@vger.kernel.org" References: <1354745355.79857.YahooMailNeo@web140001.mail.bf1.yahoo.com> <20121205222738.GB6239@liondog.tnic> <1354748412.17691.YahooMailNeo@web140005.mail.bf1.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1354748412.17691.YahooMailNeo@web140005.mail.bf1.yahoo.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 05, 2012 at 03:00:12PM -0800, John wrote: > > This only makes sense if you can show a noticeable performance > > > improvement using one of the those -march options with at least one > > benchmark from those which we have now in the kernel. > > Thank you for the feedback, Boris.  Can you point me to the built in > benchmarks to which you referred?  I am interested in probing this > further. Maybe the easiest thing to do is build the kernel: make -j in your kernel directory and time it. You could get more precise output if you trace that workload with perf: $ perf stat --repeat 10 make -j And look at how the perf output looks like. For all those runs, you need hardware supporting any of these options and the running kernel should each time be built with a different optimization option. This will show us whether differently optimized kernels show any performance difference. And then you can go and try other benchmarks like kernbench, hackbench, etc, whatever your favourite search engine gives you for "linux benchmarks" HTH. -- Regards/Gruss, Boris.