Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756982Ab1FUQVT (ORCPT ); Tue, 21 Jun 2011 12:21:19 -0400 Received: from smtp-out.google.com ([216.239.44.51]:61221 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754354Ab1FUQVS (ORCPT ); Tue, 21 Jun 2011 12:21:18 -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; b=jyWd52Co+0NWA5znyz6SaOaXWRVx8od17oFHLWmmWIqvlamx5HWtbCJevFOqBhbYis 1Cbe8xatgNgAb0zBo5Hw== MIME-Version: 1.0 In-Reply-To: References: <4DB989B5.1030703@openvz.org> <20110621152301.GA5155@redhat.com> <1308671933.26237.183.camel@twins> Date: Tue, 21 Jun 2011 18:20:56 +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 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2097 Lines: 49 Cyrill, [repost because of MIME crap] I admit I don't quite understand how this patch works around the limitation. In the end you are still going to program some cycle event into a P4 PMU register. So how it is going to free more counters for regular users? On Tue, Jun 21, 2011 at 6:13 PM, Cyrill Gorcunov wrote: > > Ok, I'll take a look (sorry for top posting, ISP problem) > > On Tuesday, June 21, 2011, Peter Zijlstra wrote: > > On Tue, 2011-06-21 at 19:40 +0400, Cyrill Gorcunov wrote: > >> On Tue, Jun 21, 2011 at 7:23 PM, Don Zickus wrote: > >> > On Thu, Apr 28, 2011 at 07:37:25PM +0400, Cyrill Gorcunov wrote: > >> >> Due to restriction and specifics of Netburst PMU we need a separated > >> >> event for NMI watchdog. In particular every Netburst event consume not > >> >> just a counter and config register, but also an additional ESCR register. > >> >> Since ESCR registers are grouped upon counters (i.e. if ESCR is occupied > >> >> for some event there is no room for another event to enter the room until > >> >> it's released) we need to pick up "least" used ESCR (or most available) > >> >> for nmi-watchdog purpose -- MSR_P4_CRU_ESCR2/3 was chosen. > >> >> > >> >> Note that on all other PMUs which support relocation of events between > >> >> counters this event is a simple alias for PERF_COUNT_HW_CPU_CYCLES. > >> > > >> > Cyril, > >> > > >> > What ever happened with this patch? > >> > > >> > Cheers, > >> > Don > >> > > >> > >> Well, it's flowing around, I didn't get any more Ack's other than your. Since it > >> introduces kind of abi I presume more ack's would be welcome before it > >> (possibly) get merged. > > > > we could avoid that abi thing by simply not making it an exposed event > > > > Its not like userspace ever should be using it anyway > > -- 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/