Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752700Ab0KWKAv (ORCPT ); Tue, 23 Nov 2010 05:00:51 -0500 Received: from smtp-out.google.com ([216.239.44.51]:52789 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751024Ab0KWKAu (ORCPT ); Tue, 23 Nov 2010 05:00:50 -0500 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=o8au/Gnfly2ueTb1q5lhuNi8A5bklvMR4r4lyKH/rIc4FELZJF+isC2MYV1eYQmsEo 1HSeLcjy78vgAd4ZmCoQ== MIME-Version: 1.0 In-Reply-To: <1290361473.2153.39.camel@laptop> References: <1290340877.2245.124.camel@localhost> <8e9ff9280b0c4a059bc82b5c4a629897.squirrel@www.firstfloor.org> <1290348259.2245.172.camel@localhost> <1290361473.2153.39.camel@laptop> Date: Tue, 23 Nov 2010 11:00:46 +0100 Message-ID: Subject: Re: [RFC PATCH 2/3 v2] perf: Implement Nehalem uncore pmu From: Stephane Eranian To: Peter Zijlstra Cc: Lin Ming , Andi Kleen , Ingo Molnar , lkml , Frederic Weisbecker , Arjan van de Ven 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: 1285 Lines: 28 On Sun, Nov 21, 2010 at 6:44 PM, Peter Zijlstra wrote: > On Sun, 2010-11-21 at 22:04 +0800, Lin Ming wrote: >> On Sun, 2010-11-21 at 20:46 +0800, Andi Kleen wrote: >> > > >> > > 2. Uncore pmu NMI handling >> > > >> > > All the 4 cores are programmed to receive uncore counter overflow >> > > interrupt. The NMI handler(running on 1 of the 4 cores) handle all >> > > counters enabled by all 4 cores. >> > >> > Really for uncore monitoring there is no need to use an NMI handler. >> > You can't profile a core anyways, so you can just delay the reporting >> > a little bit. It may simplify the code to not use one here >> > and just use an ordinary handler. >> >> OK, I can use on ordinary interrupt handler here. > > Does the hardware actually allow using a different interrupt source? > It does not. It's using whatever you've programmed into the APIC LVT vector, AFAIK. Uncore interrupt mode is enabled via IA32_DEBUGCTL. Regarless of sampling or not, you need the interrupt to virtualize the counters to 64 bits. -- 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/