From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752535AbaJSWHr (ORCPT ); Sun, 19 Oct 2014 18:07:47 -0400 Received: from mga11.intel.com ([192.55.52.93]:34011 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752114AbaJSWFi (ORCPT ); Sun, 19 Oct 2014 18:05:38 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,862,1389772800"; d="scan'208";a="402644505" From: Kan Liang To: a.p.zijlstra@chello.nl, eranian@google.com Cc: linux-kernel@vger.kernel.org, mingo@redhat.com, paulus@samba.org, acme@kernel.org, jolsa@redhat.com, ak@linux.intel.com, Kan Liang , "Yan, Zheng" Subject: [PATCH V6 13/17] perf, x86: enable LBR callstack when recording callchain Date: Sun, 19 Oct 2014 17:55:08 -0400 Message-Id: <1413755712-8259-14-git-send-email-kan.liang@intel.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1413755712-8259-1-git-send-email-kan.liang@intel.com> References: <1413755712-8259-1-git-send-email-kan.liang@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Only enable LBR callstack when user requires fp callgraph. The feature is not available when PERF_SAMPLE_BRANCH_STACK or PERF_SAMPLE_STACK_USER is required. Also, this feature only affects how to get user callchain. The kernel callchain is always got by frame pointers. Signed-off-by: Yan, Zheng Signed-off-by: Kan Liang --- arch/x86/kernel/cpu/perf_event.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 9656b9e..b3256a3 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -424,10 +424,24 @@ int x86_pmu_hw_config(struct perf_event *event) if (!event->attr.exclude_kernel) *br_type |= PERF_SAMPLE_BRANCH_KERNEL; } - } + } else if (x86_pmu_has_lbr_callstack() && + (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) && + !(event->attr.sample_type & PERF_SAMPLE_STACK_USER) && + !has_branch_stack(event) && + !event->attr.exclude_user && + (event->attach_state & PERF_ATTACH_TASK)) { + /* + * user did not specify branch_sample_type, + * try using the LBR call stack facility to + * record call chains of user program. + */ + event->attr.branch_sample_type = + PERF_SAMPLE_BRANCH_USER | + PERF_SAMPLE_BRANCH_CALL_STACK; - if (event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_CALL_STACK) + /* needs PMU specific data to save LBR stack */ event->attach_state |= PERF_ATTACH_TASK_DATA; + } /* * Generate PMC IRQs: -- 1.8.3.2