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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 348C9C32772 for ; Tue, 23 Aug 2022 22:12:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232908AbiHWWMz (ORCPT ); Tue, 23 Aug 2022 18:12:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232965AbiHWWMW (ORCPT ); Tue, 23 Aug 2022 18:12:22 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 618897C192 for ; Tue, 23 Aug 2022 15:11:12 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id q7-20020a63e947000000b004297f1e1f86so6665868pgj.12 for ; Tue, 23 Aug 2022 15:11:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:from:to:cc; bh=XPuMrEmpVaX0CO7dyFJBelQFPDb3Vcz70HxeyCf+Aoo=; b=SJ+8921Gu9b3/VmEZj1EADQgc2FMFPsv+iqRwwG5/DLfP5x1WL5CBnZHQEUET2dwDf XCIywGXcF2XdS/+7+k9pj4eDl7frNGPb65KPPdKE101o4g6KTeZpDK6CGNKG00b0ITNl zyDdmGb4gNTgLzAqH4Tjy2oJzOgCcHLXJBlNtbKjB6XEVu49IDYwo+amTX33qly9RRwv rwDvxWdmjvQRM8UsDDWP5uyogTrGHTO2VgNeNSTn06gT7UylBKz+LA4jtwbG1NOPNYJo dzhQ6/kVIZUwVds8WBpBKWKtDjgoVl+bezYgHud5Lxcb045ct0ESDcPS4o48YA9GuyiX cz8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:x-gm-message-state:from:to:cc; bh=XPuMrEmpVaX0CO7dyFJBelQFPDb3Vcz70HxeyCf+Aoo=; b=V/uPrBj3uz+wC205v8gYYm1j9wgoJkiHk4D9KOcw8nuXpOqrtRAjNWDeMGvqokT6e1 QM/F5hjb34IZ7BU4hy8TBHYxpTQpbtyLl/uFn/715Ih9Fc7cfNkTB0FKLNDjeYQ1PQjk s12xq4K9DRjC33V8bW/Mwa+yVu7tH2KBl7g0QFoEU3Do7ZBBKZ/lIi7r2aqnlDoyKqY1 g1FZbq1/B4EIHyznBxYzXZ9JMgNZ4zBPHFUmsxoO2BqY+b5tpIO5e0FC4JONAXDDAzKI AxoBel8sXu6c8O66dq1mUQ99+q0GVjtgXXuuq4QtZtDm6pGKRhFp6XB6LlwDozQpenEz c6pg== X-Gm-Message-State: ACgBeo0ZaVZuRVKmOThMCEo8fSRimHcg04bFzDJ8Hsirs6HwhXdc8GrT 6OFHQ/8qS12Fl2SwinD0yUZbD3inEuyt X-Google-Smtp-Source: AA6agR6/lrrbVHDvzAtqYEgzKbOP+OGUUywQemY8hrKQaj9m/YTAfzeBeCgzyMm2qKvm/cIwWjLpEYwnDh/O X-Received: from irogers.svl.corp.google.com ([2620:15c:2d4:203:7dbd:c08f:de81:c2a3]) (user=irogers job=sendgmr) by 2002:a17:902:d505:b0:173:111a:3023 with SMTP id b5-20020a170902d50500b00173111a3023mr1535558plg.32.1661292670931; Tue, 23 Aug 2022 15:11:10 -0700 (PDT) Date: Tue, 23 Aug 2022 15:09:20 -0700 In-Reply-To: <20220823220922.256001-1-irogers@google.com> Message-Id: <20220823220922.256001-17-irogers@google.com> Mime-Version: 1.0 References: <20220823220922.256001-1-irogers@google.com> X-Mailer: git-send-email 2.37.2.609.g9ff673ca1a-goog Subject: [PATCH v2 16/18] perf sched: Fixes for thread safety analysis From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Thomas Gleixner , Darren Hart , Davidlohr Bueso , "=?UTF-8?q?Andr=C3=A9=20Almeida?=" , Nathan Chancellor , Nick Desaulniers , Tom Rix , Weiguo Li , Athira Rajeev , Thomas Richter , Ravi Bangoria , Dario Petrillo , Hewenliang , yaowenbin , Wenyu Liu , Song Liu , Andrii Nakryiko , Dave Marchevsky , Leo Yan , Kim Phillips , Pavithra Gurushankar , Alexandre Truong , Quentin Monnet , William Cohen , Andres Freund , Adrian Hunter , "=?UTF-8?q?Martin=20Li=C5=A1ka?=" , Colin Ian King , James Clark , Fangrui Song , Stephane Eranian , Kajol Jain , Alexey Bayduraev , Riccardo Mancini , Andi Kleen , Masami Hiramatsu , Zechuan Chen , Jason Wang , Christophe JAILLET , Remi Bernon , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, bpf@vger.kernel.org, llvm@lists.linux.dev Cc: Ian Rogers Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add annotations to describe lock behavior. Add unlocks so that mutexes aren't conditionally held on exit from perf_sched__replay. Add an exit variable so that thread_func can terminate, rather than leaving the threads blocked on mutexes. Signed-off-by: Ian Rogers --- tools/perf/builtin-sched.c | 46 ++++++++++++++++++++++++-------------- 1 file changed, 29 insertions(+), 17 deletions(-) diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index 0f52f73be896..ce8497d39f9c 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -246,6 +246,7 @@ struct perf_sched { const char *time_str; struct perf_time_interval ptime; struct perf_time_interval hist_time; + volatile bool thread_funcs_exit; }; /* per thread run time data */ @@ -633,31 +634,34 @@ static void *thread_func(void *ctx) prctl(PR_SET_NAME, comm2); if (fd < 0) return NULL; -again: - ret = sem_post(&this_task->ready_for_work); - BUG_ON(ret); - mutex_lock(&sched->start_work_mutex); - mutex_unlock(&sched->start_work_mutex); - cpu_usage_0 = get_cpu_usage_nsec_self(fd); + while (!sched->thread_funcs_exit) { + ret = sem_post(&this_task->ready_for_work); + BUG_ON(ret); + mutex_lock(&sched->start_work_mutex); + mutex_unlock(&sched->start_work_mutex); - for (i = 0; i < this_task->nr_events; i++) { - this_task->curr_event = i; - perf_sched__process_event(sched, this_task->atoms[i]); - } + cpu_usage_0 = get_cpu_usage_nsec_self(fd); - cpu_usage_1 = get_cpu_usage_nsec_self(fd); - this_task->cpu_usage = cpu_usage_1 - cpu_usage_0; - ret = sem_post(&this_task->work_done_sem); - BUG_ON(ret); + for (i = 0; i < this_task->nr_events; i++) { + this_task->curr_event = i; + perf_sched__process_event(sched, this_task->atoms[i]); + } - mutex_lock(&sched->work_done_wait_mutex); - mutex_unlock(&sched->work_done_wait_mutex); + cpu_usage_1 = get_cpu_usage_nsec_self(fd); + this_task->cpu_usage = cpu_usage_1 - cpu_usage_0; + ret = sem_post(&this_task->work_done_sem); + BUG_ON(ret); - goto again; + mutex_lock(&sched->work_done_wait_mutex); + mutex_unlock(&sched->work_done_wait_mutex); + } + return NULL; } static void create_tasks(struct perf_sched *sched) + EXCLUSIVE_LOCK_FUNCTION(sched->start_work_mutex) + EXCLUSIVE_LOCK_FUNCTION(sched->work_done_wait_mutex) { struct task_desc *task; pthread_attr_t attr; @@ -687,6 +691,8 @@ static void create_tasks(struct perf_sched *sched) } static void wait_for_tasks(struct perf_sched *sched) + EXCLUSIVE_LOCKS_REQUIRED(sched->work_done_wait_mutex) + EXCLUSIVE_LOCKS_REQUIRED(sched->start_work_mutex) { u64 cpu_usage_0, cpu_usage_1; struct task_desc *task; @@ -738,6 +744,8 @@ static void wait_for_tasks(struct perf_sched *sched) } static void run_one_test(struct perf_sched *sched) + EXCLUSIVE_LOCKS_REQUIRED(sched->work_done_wait_mutex) + EXCLUSIVE_LOCKS_REQUIRED(sched->start_work_mutex) { u64 T0, T1, delta, avg_delta, fluct; @@ -3309,11 +3317,15 @@ static int perf_sched__replay(struct perf_sched *sched) print_task_traces(sched); add_cross_task_wakeups(sched); + sched->thread_funcs_exit = false; create_tasks(sched); printf("------------------------------------------------------------\n"); for (i = 0; i < sched->replay_repeat; i++) run_one_test(sched); + sched->thread_funcs_exit = true; + mutex_unlock(&sched->start_work_mutex); + mutex_unlock(&sched->work_done_wait_mutex); return 0; } -- 2.37.2.609.g9ff673ca1a-goog