From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751721AbeDIHZl (ORCPT ); Mon, 9 Apr 2018 03:25:41 -0400 Received: from mga09.intel.com ([134.134.136.24]:10170 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750759AbeDIHZi (ORCPT ); Mon, 9 Apr 2018 03:25:38 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,426,1517904000"; d="scan'208";a="45318238" Subject: [PATCH v5 1/3] perf/core: store context switch out type into Perf trace From: Alexey Budankov To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo Cc: Alexander Shishkin , Jiri Olsa , Namhyung Kim , Andi Kleen , linux-kernel , linux-perf-users@vger.kernel.org References: Organization: Intel Corp. Message-ID: <9ff84e83-a0ca-dd82-a6d0-cb951689be74@linux.intel.com> Date: Mon, 9 Apr 2018 10:25:32 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Store preempting context switch out event into Perf trace as a part of PERF_RECORD_SWITCH[_CPU_WIDE] record. Percentage of preempting and non-preempting context switches help understanding the nature of workloads (CPU or IO bound) that are running on a machine; The event is treated as preemption one when task->state value of the thread being switched out is TASK_RUNNING. Event type encoding is implemented using PERF_RECORD_MISC_SWITCH_OUT_PREEMPT bit; Signed-off-by: Alexey Budankov --- include/uapi/linux/perf_event.h | 18 +++++++++++++++--- kernel/events/core.c | 4 ++++ tools/include/uapi/linux/perf_event.h | 18 +++++++++++++++--- 3 files changed, 34 insertions(+), 6 deletions(-) diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 912b85b52344..b8e288a1f740 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -650,11 +650,23 @@ struct perf_event_mmap_page { #define PERF_RECORD_MISC_COMM_EXEC (1 << 13) #define PERF_RECORD_MISC_SWITCH_OUT (1 << 13) /* - * Indicates that the content of PERF_SAMPLE_IP points to - * the actual instruction that triggered the event. See also - * perf_event_attr::precise_ip. + * These PERF_RECORD_MISC_* flags below are safely reused + * for the following events: + * + * PERF_RECORD_MISC_EXACT_IP - PERF_RECORD_SAMPLE of precise events + * PERF_RECORD_MISC_SWITCH_OUT_PREEMPT - PERF_RECORD_SWITCH* events + * + * + * PERF_RECORD_MISC_EXACT_IP: + * Indicates that the content of PERF_SAMPLE_IP points to + * the actual instruction that triggered the event. See also + * perf_event_attr::precise_ip. + * + * PERF_RECORD_MISC_SWITCH_OUT_PREEMPT: + * Indicates that thread was preempted in TASK_RUNNING state. */ #define PERF_RECORD_MISC_EXACT_IP (1 << 14) +#define PERF_RECORD_MISC_SWITCH_OUT_PREEMPT (1 << 14) /* * Reserve the last bit to indicate some extended misc field */ diff --git a/kernel/events/core.c b/kernel/events/core.c index fc1c330c6bd6..872a5aaa77eb 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7584,6 +7584,10 @@ static void perf_event_switch(struct task_struct *task, }, }; + if (!sched_in && task->state == TASK_RUNNING) + switch_event.event_id.header.misc |= + PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; + perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h index 912b85b52344..b8e288a1f740 100644 --- a/tools/include/uapi/linux/perf_event.h +++ b/tools/include/uapi/linux/perf_event.h @@ -650,11 +650,23 @@ struct perf_event_mmap_page { #define PERF_RECORD_MISC_COMM_EXEC (1 << 13) #define PERF_RECORD_MISC_SWITCH_OUT (1 << 13) /* - * Indicates that the content of PERF_SAMPLE_IP points to - * the actual instruction that triggered the event. See also - * perf_event_attr::precise_ip. + * These PERF_RECORD_MISC_* flags below are safely reused + * for the following events: + * + * PERF_RECORD_MISC_EXACT_IP - PERF_RECORD_SAMPLE of precise events + * PERF_RECORD_MISC_SWITCH_OUT_PREEMPT - PERF_RECORD_SWITCH* events + * + * + * PERF_RECORD_MISC_EXACT_IP: + * Indicates that the content of PERF_SAMPLE_IP points to + * the actual instruction that triggered the event. See also + * perf_event_attr::precise_ip. + * + * PERF_RECORD_MISC_SWITCH_OUT_PREEMPT: + * Indicates that thread was preempted in TASK_RUNNING state. */ #define PERF_RECORD_MISC_EXACT_IP (1 << 14) +#define PERF_RECORD_MISC_SWITCH_OUT_PREEMPT (1 << 14) /* * Reserve the last bit to indicate some extended misc field */