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 16796CA9EAE for ; Wed, 23 Oct 2019 07:13:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E51322084C for ; Wed, 23 Oct 2019 07:13:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389855AbfJWHNA (ORCPT ); Wed, 23 Oct 2019 03:13:00 -0400 Received: from mga12.intel.com ([192.55.52.136]:5193 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732481AbfJWHNA (ORCPT ); Wed, 23 Oct 2019 03:13:00 -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 fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Oct 2019 00:13:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,219,1569308400"; d="scan'208";a="372790689" Received: from linux.intel.com ([10.54.29.200]) by orsmga005.jf.intel.com with ESMTP; 23 Oct 2019 00:12:59 -0700 Received: from [10.249.230.188] (abudanko-mobl.ccr.corp.intel.com [10.249.230.188]) by linux.intel.com (Postfix) with ESMTP id 3557B58048F; Wed, 23 Oct 2019 00:12:55 -0700 (PDT) Subject: [PATCH v5 3/4] perf/x86/intel: implement LBR callstacks context synchronization From: Alexey Budankov To: Peter Zijlstra Cc: Arnaldo Carvalho de Melo , Ingo Molnar , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Andi Kleen , Kan Liang , Stephane Eranian , Ian Rogers , Song Liu , linux-kernel References: Organization: Intel Corp. Message-ID: <261ac742-9022-c3f4-5885-1eae7415b091@linux.intel.com> Date: Wed, 23 Oct 2019 10:12:54 +0300 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: Content-Type: text/plain; charset=utf-8 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 Implement intel_pmu_lbr_swap_task_ctx() method updating counters 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 swaps the counter value with the one that is expected to be non zero at the previous equivalent task perf event context. Swap operation type ensures the previous task perf event context stays consistent with the amount of events that requested LBR callstack data on a sample. Signed-off-by: Alexey Budankov --- arch/x86/events/intel/lbr.c | 23 +++++++++++++++++++++++ arch/x86/events/perf_event.h | 3 +++ 2 files changed, 26 insertions(+) diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c index ea54634eabf3..534c76606049 100644 --- a/arch/x86/events/intel/lbr.c +++ b/arch/x86/events/intel/lbr.c @@ -417,6 +417,29 @@ 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_swap_task_ctx(struct perf_event_context *prev, + struct perf_event_context *next) +{ + struct x86_perf_task_context *prev_ctx_data, *next_ctx_data; + + swap(prev->task_ctx_data, next->task_ctx_data); + + /* + * Architecture specific synchronization makes sense in + * case both prev->task_ctx_data and next->task_ctx_data + * pointers are allocated. + */ + + prev_ctx_data = next->task_ctx_data; + next_ctx_data = prev->task_ctx_data; + + if (!prev_ctx_data || !next_ctx_data) + return; + + swap(prev_ctx_data->lbr_callstack_users, + next_ctx_data->lbr_callstack_users); +} + 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 5384317eaa16..930611db8f9a 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_swap_task_ctx(struct perf_event_context *prev, + struct perf_event_context *next); + void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in); u64 lbr_from_signext_quirk_wr(u64 val); -- 2.20.1