From patchwork Fri Jul 1 02:23:48 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 71280 Delivered-To: patch@linaro.org Received: by 10.140.28.4 with SMTP id 4csp65245qgy; Thu, 30 Jun 2016 19:27:36 -0700 (PDT) X-Received: by 10.66.101.231 with SMTP id fj7mr27464150pab.59.1467340055590; Thu, 30 Jun 2016 19:27:35 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id wu1si1504922pab.81.2016.06.30.19.27.35; Thu, 30 Jun 2016 19:27:35 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752510AbcGAC1W (ORCPT + 30 others); Thu, 30 Jun 2016 22:27:22 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:10189 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751713AbcGAC1R (ORCPT ); Thu, 30 Jun 2016 22:27:17 -0400 Received: from 172.24.1.136 (EHLO szxeml432-hub.china.huawei.com) ([172.24.1.136]) by szxrg03-dlp.huawei.com (MOS 4.4.3-GA FastPath queued) with ESMTP id CEE20773; Fri, 01 Jul 2016 10:24:07 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by szxeml432-hub.china.huawei.com (10.82.67.209) with Microsoft SMTP Server id 14.3.235.1; Fri, 1 Jul 2016 10:23:58 +0800 From: Wang Nan To: , CC: , , , Wang Nan , He Kuang , "Arnaldo Carvalho de Melo" , Jiri Olsa , "Masami Hiramatsu" , Namhyung Kim , "Nilay Vaish" Subject: [PATCH v12 5/8] perf record: Read from overwritable ring buffer Date: Fri, 1 Jul 2016 02:23:48 +0000 Message-ID: <1467339831-171169-6-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1467339831-171169-1-git-send-email-wangnan0@huawei.com> References: <1467339831-171169-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.5775D449.0096, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: cf885a39af4bbd4bf146fa67babb1c23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org overwrite_evt_state is introduced to reflect the state of overwritable ring buffers. It is a state machine with 3 states: .________________(forbid)_____________. | | | V RUNNING --(1)--> DATA_PENDING --(2)--> EMPTY ^ ^ | ^ | | |__(forbid)____/ |___(forbid)___/| | | \_________________(3)_______________/ RUNNING : Overwritable ring buffers are recording DATA_PENDING : We are required to collect overwritable ring buffers EMPTY : We have collected data from those ring buffers. (1): Pause ring buffers for reading (2): Read from ring buffers (3): Resume ring buffers for recording We can't avoid this complexity. Since we deliberately drop records from overwritable ring buffer, there's no way for us to check remaining from ring buffer itself (by checking head and old pointers). Therefore, we need DATA_PENDING and EMPTY state to help us recording what we have done to the ring buffer. With the above state machine, this patch improves record__mmap_read_all(), read from overwritable ring buffer when DATA_PENDING state is observed. Signed-off-by: Wang Nan Signed-off-by: He Kuang Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Zefan Li Cc: Nilay Vaish Cc: pi3orama@163.com --- tools/perf/builtin-record.c | 137 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 136 insertions(+), 1 deletion(-) -- 1.8.3.4 diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index bad6e04..7f1c4c3 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -43,6 +43,30 @@ #include #include +/* + * State machine of overwrite_evt_state: + * + * .________________(forbid)_____________. + * | V + * RUNNING --(1)--> DATA_PENDING --(2)--> EMPTY + * ^ ^ | ^ | + * | |__(forbid)____/ |___(forbid)___/| + * | | + * \_________________(3)_______________/ + * + * RUNNING : Overwritable ring buffers are recording + * DATA_PENDING : We are required to collect overwritable ring buffers + * EMPTY : We have collected data from those ring buffers. + * + * (1): Pause ring buffers for reading + * (2): Read from ring buffers + * (3): Resume ring buffers for recording + */ +enum overwrite_evt_state { + OVERWRITE_EVT_RUNNING, + OVERWRITE_EVT_DATA_PENDING, + OVERWRITE_EVT_EMPTY, +}; struct record { struct perf_tool tool; @@ -62,6 +86,7 @@ struct record { bool buildid_all; bool timestamp_filename; bool switch_output; + enum overwrite_evt_state overwrite_evt_state; unsigned long long samples; }; @@ -463,6 +488,7 @@ try_again: session->evlist = evlist; perf_session__set_id_hdr_size(session); + rec->overwrite_evt_state = OVERWRITE_EVT_RUNNING; out: return rc; } @@ -543,6 +569,79 @@ static struct perf_event_header finished_round_event = { .type = PERF_RECORD_FINISHED_ROUND, }; +static void +record__toggle_overwrite_evsels(struct record *rec, + enum overwrite_evt_state state) +{ + struct perf_evlist *evlist = rec->overwrite_evlist; + enum overwrite_evt_state old_state = rec->overwrite_evt_state; + enum action { + NONE, + PAUSE, + RESUME, + } action = NONE; + + switch (old_state) { + case OVERWRITE_EVT_RUNNING: { + switch (state) { + case OVERWRITE_EVT_DATA_PENDING: + action = PAUSE; + break; + case OVERWRITE_EVT_RUNNING: + case OVERWRITE_EVT_EMPTY: + default: + goto state_err; + } + break; + } + case OVERWRITE_EVT_DATA_PENDING: { + switch (state) { + case OVERWRITE_EVT_EMPTY: + break; + case OVERWRITE_EVT_RUNNING: + case OVERWRITE_EVT_DATA_PENDING: + default: + goto state_err; + } + break; + } + case OVERWRITE_EVT_EMPTY: { + switch (state) { + case OVERWRITE_EVT_RUNNING: + action = RESUME; + break; + case OVERWRITE_EVT_EMPTY: + case OVERWRITE_EVT_DATA_PENDING: + default: + goto state_err; + } + break; + } + default: + WARN_ONCE(1, "Shouldn't get there\n"); + } + + rec->overwrite_evt_state = state; + + if (!evlist) + return; + + switch (action) { + case PAUSE: + perf_evlist__pause(evlist); + break; + case RESUME: + perf_evlist__resume(evlist); + break; + case NONE: + default: + break; + } + +state_err: + return; +} + static int record__mmap_read_evlist(struct record *rec, struct perf_evlist *evlist) { u64 bytes_written = rec->bytes_written; @@ -588,7 +687,13 @@ static int record__mmap_read_all(struct record *rec) if (err) return err; - return err; + if (rec->overwrite_evt_state == OVERWRITE_EVT_DATA_PENDING) { + err = record__mmap_read_evlist(rec, rec->overwrite_evlist); + if (err) + return err; + record__toggle_overwrite_evsels(rec, OVERWRITE_EVT_EMPTY); + } + return 0; } static void record__init_features(struct record *rec) @@ -987,6 +1092,17 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) for (;;) { unsigned long long hits = rec->samples; + /* + * rec->overwrite_evt_state is possible to be + * OVERWRITE_EVT_EMPTY here: when done == true and + * hits != rec->samples in previous round. + * + * record__toggle_overwrite_evsels ensure we never + * convert OVERWRITE_EVT_EMPTY to OVERWRITE_EVT_DATA_PENDING. + */ + if (trigger_is_hit(&switch_output_trigger) || done || draining) + record__toggle_overwrite_evsels(rec, OVERWRITE_EVT_DATA_PENDING); + if (record__mmap_read_all(rec) < 0) { trigger_error(&auxtrace_snapshot_trigger); trigger_error(&switch_output_trigger); @@ -1006,8 +1122,27 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) } if (trigger_is_hit(&switch_output_trigger)) { + /* + * If switch_output_trigger is hit, the data in + * overwritable ring buffer should have been collected, + * so overwrite_evt_state should be set to + * OVERWRITE_EVT_EMPTY. + * + * If SIGUSR2 raise after or during record__mmap_read_all(), + * record__mmap_read_all() didn't collect data from + * overwritable ring buffer. Read again. + */ + if (rec->overwrite_evt_state == OVERWRITE_EVT_RUNNING) + continue; trigger_ready(&switch_output_trigger); + /* + * Reenable events in overwrite ring buffer after + * record__mmap_read_all(): we should have collected + * data from it. + */ + record__toggle_overwrite_evsels(rec, OVERWRITE_EVT_RUNNING); + if (!quiet) fprintf(stderr, "[ perf record: dump data: Woken up %ld times ]\n", waking);