Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752144AbaFEQj6 (ORCPT ); Thu, 5 Jun 2014 12:39:58 -0400 Received: from mail-yh0-f47.google.com ([209.85.213.47]:35362 "EHLO mail-yh0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752110AbaFEQjz (ORCPT ); Thu, 5 Jun 2014 12:39:55 -0400 MIME-Version: 1.0 In-Reply-To: <20140605151734.GD16811@pd.tnic> References: <20140605132750.GA16811@pd.tnic> <20140605140316.GB16811@pd.tnic> <20140605151734.GD16811@pd.tnic> Date: Thu, 5 Jun 2014 19:39:55 +0300 Message-ID: Subject: Re: [PATCH 9/9] perf/x86: add syfs entry to disable HT bug workaround From: Maria Dimakopoulou To: Borislav Petkov Cc: Stephane Eranian , 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 6:17 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. > -- > 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/