Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752297AbaFEQrs (ORCPT ); Thu, 5 Jun 2014 12:47:48 -0400 Received: from mail-ob0-f170.google.com ([209.85.214.170]:48129 "EHLO mail-ob0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752238AbaFEQrp (ORCPT ); Thu, 5 Jun 2014 12:47:45 -0400 MIME-Version: 1.0 In-Reply-To: References: <20140605132750.GA16811@pd.tnic> <20140605140316.GB16811@pd.tnic> <20140605151734.GD16811@pd.tnic> Date: Thu, 5 Jun 2014 18:47:44 +0200 Message-ID: Subject: Re: [PATCH 9/9] perf/x86: add syfs entry to disable HT bug workaround From: Stephane Eranian To: Maria Dimakopoulou Cc: Borislav Petkov , Matt Fleming , LKML , Peter Zijlstra , "mingo@elte.hu" , "ak@linux.intel.com" , 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 Thu, Jun 5, 2014 at 6:39 PM, Maria Dimakopoulou wrote: > On Thu, Jun 5, 2014 at 6:17 PM, Borislav Petkov wrote: >> On Thu, Jun 05, 2014 at 05:45:24PM +0300, Maria Dimakopoulou wrote: >>> The issue is that the outcoming leaked counts are not compensated >>> by the incoming leaked counts of the sibling thread. With the workaround, >>> corrupting events are always scheduled with an empty sibling counter. >>> This means that their leaked counts are lost. So it is expected to see >>> lower counts with the workaround. Note that this is not a side-effect of >>> the workaround; leaked counts are expected to be lost with nothing >>> measured on the sibling counter in general. >>> >>> In a second series we intend to re-integrate the counts for counting mode >>> events. The workaround makes this easier because it guarantees >>> that the sibling counter is unused, thus its counts are purely leaked >>> counts and they can be safely re-integrated. >> >> IIUC, sounds to me like reintegrating the leaked counts from the unused >> counter should be part of the workaround too, not a second series... >> > > This series aims to avoid corruption of non-corrupting events. > Re-integration of the counts is not related to this. This is why > we chose to fix this other problem on a second series to keep > things clean and concepts separated. > I agree with Maria here. The reintegration is different problem. The series here helps and is a required first step. Reintegration will be added asap. >> -- >> Regards/Gruss, >> Boris. >> >> Sent from a fat crate under my desk. Formatting is fine. >> -- -- 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/