From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751988AbdBFMox (ORCPT ); Mon, 6 Feb 2017 07:44:53 -0500 Received: from mail-wm0-f68.google.com ([74.125.82.68]:33082 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751881AbdBFMow (ORCPT ); Mon, 6 Feb 2017 07:44:52 -0500 Date: Mon, 6 Feb 2017 13:44:48 +0100 From: Ingo Molnar To: Borislav Petkov Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Robert Richter , Vince Weaver , lkml Subject: Re: [RFC PATCH] perf/stat: Add --disable-hwdt Message-ID: <20170206124447.GA12772@gmail.com> References: <20170206121506.mtknwusus4djp2sx@pd.tnic> <20170206122231.GA9404@gmail.com> <20170206124116.7jmrmufthqtnd3dc@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170206124116.7jmrmufthqtnd3dc@pd.tnic> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Borislav Petkov wrote: > On Mon, Feb 06, 2017 at 01:22:31PM +0100, Ingo Molnar wrote: > > Looks sensible, and I'd in fact make this the new default behavior (if root runs > > perf stat) - i.e. add a flag to re-enable it, for the rare case where we want to > > debug a hard deadlock while running perf stat ... > > I'd probably only need to save the previous state, in case it was > disabled for whatever reason. > > So actually, I'll make it so that we restore the previous state at exit. > Whatever it was. But while perf stat runs as root, we will disable it by > default. > > /me scratches head a bit... > > Oh ok, even better - no need for a cmdline option then. > > Or does it *ever* make sense to have watchdog running *while* perf stat > runs too? Yeah, if for some whatever reason perf locks up while running perf stat as root, so I'd keep the option, as a general principle. :-/ Thanks, Ingo