Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751899AbaBZJAN (ORCPT ); Wed, 26 Feb 2014 04:00:13 -0500 Received: from mga02.intel.com ([134.134.136.20]:38259 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751072AbaBZJAL (ORCPT ); Wed, 26 Feb 2014 04:00:11 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,546,1389772800"; d="scan'208";a="481980318" Message-ID: <530DAC5E.20408@intel.com> Date: Wed, 26 Feb 2014 16:57:02 +0800 From: "Yan, Zheng" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Stephane Eranian , Andy Lutomirski CC: LKML , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Andi Kleen Subject: Re: [PATCH v3 00/14] perf, x86: Haswell LBR call stack support References: <1392703661-15104-1-git-send-email-zheng.z.yan@intel.com> <530D53EF.9090706@amacapital.net> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/26/2014 03:04 PM, Stephane Eranian wrote: > On Wed, Feb 26, 2014 at 3:39 AM, Andy Lutomirski wrote: >> On 02/17/2014 10:07 PM, Yan, Zheng wrote: >>> >>> This patch series adds LBR call stack support. User can enabled/disable >>> this through an sysfs attribute file in the CPU PMU directory: >>> echo 1 > /sys/bus/event_source/devices/cpu/lbr_callstack >> >> This seems like an unpleasant way to control this. It would be handy to >> be able to control this as an option to perf record. >> > That would mean you'd be root for perf. > Or are you suggesting a perf event option? But then, you'd expose arch-specific > feature at the API level. > Another option is enable this feature by default if hardware supports it. But it causes LBR contention between events that want callstack and evnets that want LBR. Regards Yan, Zheng -- 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/