Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754113AbbEKQcs (ORCPT ); Mon, 11 May 2015 12:32:48 -0400 Received: from mail-oi0-f43.google.com ([209.85.218.43]:35566 "EHLO mail-oi0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751951AbbEKQce (ORCPT ); Mon, 11 May 2015 12:32:34 -0400 MIME-Version: 1.0 In-Reply-To: <20150511162354.GA21418@twins.programming.kicks-ass.net> References: <1431285767-27027-1-git-send-email-andi@firstfloor.org> <1431285767-27027-10-git-send-email-andi@firstfloor.org> <20150511162354.GA21418@twins.programming.kicks-ass.net> Date: Mon, 11 May 2015 09:32:33 -0700 Message-ID: Subject: Re: [PATCH 9/9] x86, perf: Move PMU ACK after LBR read From: Stephane Eranian To: Peter Zijlstra Cc: Andi Kleen , LKML , Andi Kleen Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1352 Lines: 32 On Mon, May 11, 2015 at 9:23 AM, Peter Zijlstra wrote: > On Sun, May 10, 2015 at 12:22:47PM -0700, Andi Kleen wrote: >> From: Andi Kleen >> >> With Arch Perfmon v4 the PMU ack unfreezes the LBRs. So we need to do >> the PMU ack after the LBR reading, otherwise the LBRs would be polluted by the >> PMI handler. > > Hmm, we should move these last three patches before the SKL enablement > patch no, otherwise things will misbehave -- say a bisection lands in > between. > > /me shuffles patches. > >> This is a minimal change. In principle the ACK could be moved much later. > > Right, so the more complete change would be to use the new and improved > FREEZE_ON_PMI and reenable both the LBRs and the CTRs with the > STATUS_RESET MSR, right? > > Does it make sense to have a new handle_irq() routine for that? Were we not already using FREEZE_ON_PMI with LBR (except for one erratum on HSW)? It would make sense to me to have an "optimized" and clean handle_irq for the newer PMU. We the caveat that any change to the core of it would now have to be done twice. -- 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/