Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757128Ab1FUR0Z (ORCPT ); Tue, 21 Jun 2011 13:26:25 -0400 Received: from smtp-out.google.com ([216.239.44.51]:26528 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753478Ab1FUR0Y convert rfc822-to-8bit (ORCPT ); Tue, 21 Jun 2011 13:26:24 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=XTYtvF+V1fSYWh7q+QBfZRC5inixRoGPV4IV9YjXWI4Kl0mNVNlAmjfIY4J1fO3sSZ qwovuN0CLaX14sskFYDg== MIME-Version: 1.0 In-Reply-To: <20110621172319.GE21641@sun> References: <4DB989B5.1030703@openvz.org> <20110621152301.GA5155@redhat.com> <1308671933.26237.183.camel@twins> <20110621164820.GC21641@sun> <20110621172319.GE21641@sun> Date: Tue, 21 Jun 2011 19:26:16 +0200 Message-ID: Subject: Re: [RFC -tip] perf, x86: Add PERF_COUNT_HW_NMI_WATCHDOG event v2 From: Stephane Eranian To: Cyrill Gorcunov Cc: Peter Zijlstra , Don Zickus , Ingo Molnar , Lin Ming , Arnaldo Carvalho de Melo , Frederic Weisbecker , Vince Weaver , lkml Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1931 Lines: 41 On Tue, Jun 21, 2011 at 7:23 PM, Cyrill Gorcunov wrote: > On Tue, Jun 21, 2011 at 07:10:05PM +0200, Stephane Eranian wrote: > ... >> > >> >  The key here is that we use that named non-sleeping ticks (as oprofile >> > did) for nmi-watchdog and it allows us to free "cpu-cycles" counter for >> > user needs. Of course we pick up one counter for this but it doesn't intersect >> > with "cpu-cycles" counter (because counters are grouped and can count only >> > specified events in each group). Stepane, should I post more details? >> > >> Ok, so you're using a different PMU event for the watchdog. But then, in this >> case why not simply change kernel/watchdog.c to hardcode something specific >> for P4, i.e, change the wd_hw_attr.config/type fields to match the >> event you want. > >  It doesn't change things much. Of course I can put some specifics into > .config but where is the guarantee some new generic event would not ever > intersect with it. I know (for example) we could reserve -1ULL for this > event but again where is the guarantee that it will never ever be used > system wide in future for some different event? > I am not talking about a new generic PMU event. I am talking about you hardcoding a raw event in the callback: type = PERF_TYPE_RAW, config=0x003c. > So I need some event-id in which I may be sure it will never be > used for different purpose. > >> You could create a arch specific callback to setup config/type. >> >> I don't think it makes sense to expose yet another generic PMU event, especially >> given the name you gave to it and what it actually does. People might wonder >> what good is that for? > >        Cyrill > -- 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/