Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756535Ab3IZIcm (ORCPT ); Thu, 26 Sep 2013 04:32:42 -0400 Received: from mga02.intel.com ([134.134.136.20]:31130 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751886Ab3IZI2V (ORCPT ); Thu, 26 Sep 2013 04:28:21 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.90,983,1371106800"; d="scan'208";a="401278439" From: "Yan, Zheng" To: linux-kernel@vger.kernel.org Cc: a.p.zijlstra@chello.nl, eranian@google.com, andi@firstfloor.org, "Yan, Zheng" Subject: [RFC PATCH 0/7] perf, x86: Reduce lbr_sel_map size Date: Thu, 26 Sep 2013 16:28:06 +0800 Message-Id: <1380184093-8838-1-git-send-email-zheng.z.yan@intel.com> X-Mailer: git-send-email 1.8.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1144 Lines: 25 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 main change since previous patch series is: Patch 3 introduces PMU context switch callback, and uses the callback to unify the flush branch stack codeo. Patch 4 uses the context switch callback to save/restore the LBR stack. 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/