From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759630Ab3BYCCE (ORCPT ); Sun, 24 Feb 2013 21:02:04 -0500 Received: from mga14.intel.com ([143.182.124.37]:23370 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759559Ab3BYCB6 (ORCPT ); Sun, 24 Feb 2013 21:01:58 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,730,1355126400"; d="scan'208";a="205839710" From: "Yan, Zheng" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, a.p.zijlstra@chello.nl, eranian@google.com, andi@firstfloor.org, "Yan, Zheng" Subject: [PATCH V3 0/7] perf, x86: Haswell LBR call stack support Date: Mon, 25 Feb 2013 10:01:20 +0800 Message-Id: <1361757687-5415-1-git-send-email-zheng.z.yan@intel.com> X-Mailer: git-send-email 1.7.11.7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Yan, Zheng" Haswell has a new feature that utilizes the existing Last Branch Record facility to record call chains. When the feature is enabled, function call will be collected as normal, but as return instructions are executed the last captured branch record is popped from the on-chip LBR registers. The LBR call stack facility can help perf to get call chains of progam without frame pointer. When perf tool requests PERF_SAMPLE_CALLCHAIN + PERF_SAMPLE_BRANCH_USER, this feature is dynamically enabled by default. This feature can be disabled/enabled through an attribute file in the cpu pmu sysfs directory. The LBR call stack has following known limitations 1. Zero length calls are not filtered out by hardware 2. Exception handing such as setjmp/longjmp will have calls/returns not match 3. Pushing different return address onto the stack will have calls/returns not match These patches are based upon Andi's linux-misc hsw/pmu5 Available from https://github.com/ukernel/linux.git hws/pmu5 Regards Yan, Zheng --- Changes since v1 - not expose PERF_SAMPLE_BRANCH_CALL_STACK to user space - save/restore LBR stack on context switch for all sampling branch modes - reduce lbr_sel_map size Changes since v2 - only enable LBR call stack when user requests sampling user callchain