Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752465AbaFFI2F (ORCPT ); Fri, 6 Jun 2014 04:28:05 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:61036 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751098AbaFFI2C (ORCPT ); Fri, 6 Jun 2014 04:28:02 -0400 MIME-Version: 1.0 X-Originating-IP: [90.207.204.193] In-Reply-To: <20140605232949.GF16855@tassilo.jf.intel.com> References: <20140605132750.GA16811@pd.tnic> <20140605140316.GB16811@pd.tnic> <20140605151734.GD16811@pd.tnic> <20140605165213.GI16642@pd.tnic> <20140605232949.GF16855@tassilo.jf.intel.com> Date: Fri, 6 Jun 2014 09:28:00 +0100 Message-ID: Subject: Re: [PATCH 9/9] perf/x86: add syfs entry to disable HT bug workaround From: Matt Fleming To: Andi Kleen Cc: Maria Dimakopoulou , Borislav Petkov , Stephane Eranian , LKML , Peter Zijlstra , "mingo@elte.hu" , Jiri Olsa , "Yan, Zheng" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6 June 2014 00:29, Andi Kleen wrote: >> As Stephane pointed out, the sysfs entry is optional and the workaround >> can be disabled only as root. >> >> It is not absolutely necessary and it's not important. >> We will drop it in V2. > > I would prefer to keep it. It's fairly complex and it's always good > to have a way to disable complex things in case something goes wrong. You want to be able to disable the workaround in case it doesn't work? I'm having a hard time buying that as a valid reason for this knob. If someone runs into issues with the workaround we want them to report those issues so that we can tweak the code. If they've got the ability to simply disable the code they're less likely to report the problem and we'll all be worse for it. Having the knob increase the number of configurations and increases complexity, it doesn't reduce it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/