Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932134AbbEKQnq (ORCPT ); Mon, 11 May 2015 12:43:46 -0400 Received: from mail-oi0-f52.google.com ([209.85.218.52]:34625 "EHLO mail-oi0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752679AbbEKQnm (ORCPT ); Mon, 11 May 2015 12:43:42 -0400 MIME-Version: 1.0 In-Reply-To: <20150511163605.GB21418@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> <20150511163605.GB21418@twins.programming.kicks-ass.net> Date: Mon, 11 May 2015 09:43:41 -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: 1649 Lines: 41 On Mon, May 11, 2015 at 9:36 AM, Peter Zijlstra wrote: > On Mon, May 11, 2015 at 09:32:33AM -0700, Stephane Eranian wrote: >> >> 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)? > > That's FREEZE_LBRS_ON_PMI, I was referring to FREEZE_PERFMON_ON_PMI, > which we've not used so far. > Ah, yes that one was not used so far. I don't quite remember why. I think with PEBS, you don't need it or it should be off or something like this. > I think Andi tried using it before, but there's some issues with it on > v3, but v4 should have fixed all that. > I was referring to a LBR issue on v3 (HSW) and call stack mode. > Andi can you perhaps explain what the problem with FREEZE_PERFMON_ON_PMI > on v3 was again? > Andi, Is that what I am alluding to above? >> 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. > > We could pull that out in a shared function of course, if possible. Good. -- 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/