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[209.132.180.67]) by mx.google.com with ESMTP id ku4si16585919pab.87.2014.11.03.16.29.45 for ; Mon, 03 Nov 2014 16:29:45 -0800 (PST) Received-SPF: none (google.com: linux-kernel-owner@vger.kernel.org does not designate permitted sender hosts) client-ip=209.132.180.67; Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751837AbaKDA3m (ORCPT + 25 others); Mon, 3 Nov 2014 19:29:42 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:52462 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751638AbaKDA3G (ORCPT ); Mon, 3 Nov 2014 19:29:06 -0500 Received: from foss-smtp-na-1.foss.arm.com (unknown [10.80.61.8]) by foss-mx-na.foss.arm.com (Postfix) with ESMTP id E97FB4E1; Mon, 3 Nov 2014 18:29:02 -0600 (CST) Received: from collaborate-mta1.arm.com (highbank-bc01-b06.austin.arm.com [10.112.81.134]) by foss-smtp-na-1.foss.arm.com (Postfix) with ESMTP id 988355FAD7; Mon, 3 Nov 2014 18:29:00 -0600 (CST) Received: from rojo.cambridge.arm.com (unknown [10.37.23.91]) by collaborate-mta1.arm.com (Postfix) with ESMTP id 6E11D13F91E; Mon, 3 Nov 2014 18:28:56 -0600 (CST) From: Pawel Moll To: Richard Cochran , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Paul Mackerras , Arnaldo Carvalho de Melo , John Stultz , Masami Hiramatsu , Christopher Covington , Namhyung Kim , David Ahern , Thomas Gleixner , Tomeu Vizoso Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Pawel Moll , Pawel Moll Subject: [PATCH v3 3/3] perf: Sample additional clock value Date: Tue, 4 Nov 2014 00:28:38 +0000 Message-Id: <1415060918-19954-4-git-send-email-pawel.moll@arm.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1415060918-19954-1-git-send-email-pawel.moll@arm.com> References: <1415060918-19954-1-git-send-email-pawel.moll@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: list List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: pawel.moll@arm.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.217.171 as permitted sender) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , From: Pawel Moll This patch adds an option to sample value of an additional clock with any perf event, with the the aim of allowing time correlation between data coming from perf and other sources like hardware trace which is timestamped with an external clock. The idea is to generate periodic perf record containing timestamps from two different sources, sampled as close to each other as possible. This allows performing simple linear approximation: perf event other event -----O--------------+-------------O------> t_other : | : : V : -----O----------------------------O------> t_perf User can request such samples for any standard perf event, with the most obvious examples of cpu-clock (hrtimer) at selected frequency or other periodic events like sched:sched_switch. In order to do this, PERF_SAMPLE_CLOCK has to be set in struct perf_event_attr.sample_type and a type of the clock to be sampled selected by setting perf_event_attr.clock to a value corresponding to a POSIX clock clk_id (see "man 2 clock_gettime") Currently three clocks are implemented: CLOCK_REALITME = 0, CLOCK_MONOTONIC = 1 and CLOCK_MONOTONIC_RAW = 2. The clock field is 5 bits wide to allow for future extension to custom, non-POSIX clock sources(MAX_CLOCK for those is 16, see include/uapi/linux/time.h) like ARM CoreSight (hardware trace) timestamp generator. Signed-off-by: Pawel Moll --- include/linux/perf_event.h | 2 ++ include/uapi/linux/perf_event.h | 16 ++++++++++++++-- kernel/events/core.c | 30 ++++++++++++++++++++++++++++++ 3 files changed, 46 insertions(+), 2 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 867415d..395d6ed 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -607,6 +607,8 @@ struct perf_sample_data { * Transaction flags for abort events: */ u64 txn; + /* Clock value (additional timestamp for time correlation) */ + u64 clock; }; /* default value for data source */ diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 9a64eb1..53a7a72 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -137,8 +137,9 @@ enum perf_event_sample_format { PERF_SAMPLE_DATA_SRC = 1U << 15, PERF_SAMPLE_IDENTIFIER = 1U << 16, PERF_SAMPLE_TRANSACTION = 1U << 17, + PERF_SAMPLE_CLOCK = 1U << 18, - PERF_SAMPLE_MAX = 1U << 18, /* non-ABI */ + PERF_SAMPLE_MAX = 1U << 19, /* non-ABI */ }; /* @@ -304,7 +305,16 @@ struct perf_event_attr { mmap2 : 1, /* include mmap with inode data */ comm_exec : 1, /* flag comm events that are due to an exec */ uevents : 1, /* allow uevents into the buffer */ - __reserved_1 : 38; + + /* + * clock: one of the POSIX clock IDs: + * + * 0 - CLOCK_REALTIME + * 1 - CLOCK_MONOTONIC + * 4 - CLOCK_MONOTONIC_RAW + */ + clock : 5, /* clock type */ + __reserved_1 : 33; union { __u32 wakeup_events; /* wakeup every n events */ @@ -544,6 +554,7 @@ enum perf_event_type { * { u64 id; } && PERF_SAMPLE_ID * { u64 stream_id;} && PERF_SAMPLE_STREAM_ID * { u32 cpu, res; } && PERF_SAMPLE_CPU + * { u64 clock; } && PERF_SAMPLE_CLOCK * { u64 id; } && PERF_SAMPLE_IDENTIFIER * } && perf_event_attr::sample_id_all * @@ -687,6 +698,7 @@ enum perf_event_type { * { u64 weight; } && PERF_SAMPLE_WEIGHT * { u64 data_src; } && PERF_SAMPLE_DATA_SRC * { u64 transaction; } && PERF_SAMPLE_TRANSACTION + * { u64 clock; } && PERF_SAMPLE_CLOCK * }; */ PERF_RECORD_SAMPLE = 9, diff --git a/kernel/events/core.c b/kernel/events/core.c index 3738e9c..611e2f7 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1232,6 +1232,9 @@ static void perf_event__header_size(struct perf_event *event) if (sample_type & PERF_SAMPLE_TRANSACTION) size += sizeof(data->txn); + if (sample_type & PERF_SAMPLE_CLOCK) + size += sizeof(data->clock); + event->header_size = size; } @@ -1259,6 +1262,9 @@ static void perf_event__id_header_size(struct perf_event *event) if (sample_type & PERF_SAMPLE_CPU) size += sizeof(data->cpu_entry); + if (sample_type & PERF_SAMPLE_CLOCK) + size += sizeof(data->clock); + event->id_header_size = size; } @@ -4599,6 +4605,24 @@ static void __perf_event_header__init_id(struct perf_event_header *header, data->cpu_entry.cpu = raw_smp_processor_id(); data->cpu_entry.reserved = 0; } + + if (sample_type & PERF_SAMPLE_CLOCK) { + switch (event->attr.clock) { + case CLOCK_REALTIME: + data->clock = ktime_get_real_ns(); + break; + case CLOCK_MONOTONIC: + data->clock = ktime_get_mono_fast_ns(); + break; + case CLOCK_MONOTONIC_RAW: + data->clock = ktime_get_raw_ns(); + break; + default: + data->clock = 0; + break; + } + } + } void perf_event_header__init_id(struct perf_event_header *header, @@ -4629,6 +4653,9 @@ static void __perf_event__output_id_sample(struct perf_output_handle *handle, if (sample_type & PERF_SAMPLE_CPU) perf_output_put(handle, data->cpu_entry); + if (sample_type & PERF_SAMPLE_CLOCK) + perf_output_put(handle, data->clock); + if (sample_type & PERF_SAMPLE_IDENTIFIER) perf_output_put(handle, data->id); } @@ -4857,6 +4884,9 @@ void perf_output_sample(struct perf_output_handle *handle, if (sample_type & PERF_SAMPLE_TRANSACTION) perf_output_put(handle, data->txn); + if (sample_type & PERF_SAMPLE_CLOCK) + perf_output_put(handle, data->clock); + if (!event->attr.watermark) { int wakeup_events = event->attr.wakeup_events;