Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754530Ab2JVNpI (ORCPT ); Mon, 22 Oct 2012 09:45:08 -0400 Received: from mga09.intel.com ([134.134.136.24]:34588 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753871Ab2JVNpG (ORCPT ); Mon, 22 Oct 2012 09:45:06 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.80,629,1344236400"; d="scan'208";a="230633229" Date: Mon, 22 Oct 2012 06:45:05 -0700 From: Andi Kleen To: Peter Zijlstra Cc: "Yan, Zheng" , linux-kernel@vger.kernel.org, eranian@google.com Subject: Re: [PATCH 1/6] perf, x86: Basic Haswell LBR call stack support Message-ID: <20121022134505.GG2095@tassilo.jf.intel.com> References: <1350886279-6141-1-git-send-email-zheng.z.yan@intel.com> <1350886279-6141-2-git-send-email-zheng.z.yan@intel.com> <1350902016.2768.85.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1350902016.2768.85.camel@twins> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 869 Lines: 23 On Mon, Oct 22, 2012 at 12:33:36PM +0200, Peter Zijlstra wrote: > On Mon, 2012-10-22 at 14:11 +0800, Yan, Zheng wrote: > > + /* LBR callstack does not work well with FREEZE_LBRS_ON_PMI */ > > + if (!cpuc->lbr_sel || !(cpuc->lbr_sel->config & LBR_CALL_STACK)) > > + debugctl |= DEBUGCTLMSR_FREEZE_LBRS_ON_PMI; > > How useful it is without this? How many calls between PMI and us getting > to intel_pmu_lbr_read()? We use it only for ring 3. For ring 0 we assume frame pointer or dwarf information. So the CPL filter acts as the freeze. -andi -- ak@linux.intel.com -- Speaking for myself only -- 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/