From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EFA78FA372A for ; Wed, 16 Oct 2019 12:20:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFC81205F4 for ; Wed, 16 Oct 2019 12:20:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405215AbfJPMUe (ORCPT ); Wed, 16 Oct 2019 08:20:34 -0400 Received: from mga18.intel.com ([134.134.136.126]:49868 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405187AbfJPMUd (ORCPT ); Wed, 16 Oct 2019 08:20:33 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Oct 2019 05:20:33 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,303,1566889200"; d="scan'208";a="370783308" Received: from linux.intel.com ([10.54.29.200]) by orsmga005.jf.intel.com with ESMTP; 16 Oct 2019 05:20:33 -0700 Received: from [10.251.8.200] (kliang2-mobl.ccr.corp.intel.com [10.251.8.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by linux.intel.com (Postfix) with ESMTPS id EEB375803C5; Wed, 16 Oct 2019 05:20:31 -0700 (PDT) Subject: Re: [PATCH v2 3/4] perf/x86/intel: implement LBR callstacks context synchronization To: Alexey Budankov , Peter Zijlstra Cc: Arnaldo Carvalho de Melo , Ingo Molnar , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Andi Kleen , Stephane Eranian , Ian Rogers , Song Liu , linux-kernel References: <5964c7e9-ab6f-c0d0-3dca-31196606e337@linux.intel.com> <79b0e201-479e-0e35-4ef4-3f6410ee28e4@linux.intel.com> From: "Liang, Kan" Message-ID: <56c5408c-a217-18f3-8a0d-c0bb0886f2d3@linux.intel.com> Date: Wed, 16 Oct 2019 08:20:30 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <79b0e201-479e-0e35-4ef4-3f6410ee28e4@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/16/2019 5:50 AM, Alexey Budankov wrote: > > Implement intel_pmu_lbr_sync_task_ctx() method that updates counter > of the events that requested LBR callstack data on a sample. > > The counter can be zero for the case when task context belongs to > a thread that has just come from a block on a futex and the context > contains saved (lbr_stack_state == LBR_VALID) LBR register values. > > For the values to be restored at LBR registers on the next thread's > switch-in event it copies the counter value that is expected to be > non zero from the previous equivalent task perf event context. > > Signed-off-by: Alexey Budankov > --- > arch/x86/events/intel/lbr.c | 9 +++++++++ > arch/x86/events/perf_event.h | 3 +++ > 2 files changed, 12 insertions(+) > > diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c > index ea54634eabf3..152a3f8b516a 100644 > --- a/arch/x86/events/intel/lbr.c > +++ b/arch/x86/events/intel/lbr.c > @@ -417,6 +417,15 @@ static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx) > cpuc->last_log_id = ++task_ctx->log_id; > } > > +void intel_pmu_lbr_sync_task_ctx(struct x86_perf_task_context *one, > + struct x86_perf_task_context *another) > +{ > + if (!one || !another) > + return; > + > + one->lbr_callstack_users = another->lbr_callstack_users; We may want to swap here? Thanks, Kan > +} > + > void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in) > { > struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); > diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h > index a25e6d7eb87b..3e0087c06fc9 100644 > --- a/arch/x86/events/perf_event.h > +++ b/arch/x86/events/perf_event.h > @@ -1024,6 +1024,9 @@ void intel_pmu_store_pebs_lbrs(struct pebs_lbr *lbr); > > void intel_ds_init(void); > > +void intel_pmu_lbr_sync_task_ctx(struct x86_perf_task_context *one, > + struct x86_perf_task_context *another); > + > void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in); > > u64 lbr_from_signext_quirk_wr(u64 val); >