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 9C349ECAAD5 for ; Fri, 26 Aug 2022 12:12:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231208AbiHZMMz (ORCPT ); Fri, 26 Aug 2022 08:12:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229917AbiHZMMy (ORCPT ); Fri, 26 Aug 2022 08:12:54 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 546CADDA93; Fri, 26 Aug 2022 05:12:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1661515973; x=1693051973; h=message-id:date:mime-version:subject:to:references:from: in-reply-to:content-transfer-encoding; bh=8gzeq3HsKshBpNjIIChQDXSz7Xg1mcO3yxgdPGuVa2A=; b=Gm0FsFNVYtMIw82tYTf+GLrn3cxVX3qlqqUBH0bZ7n3oEGGie4gahSGr 4xCGcZHP3iLZO09rcuwJnhjRKglQONhlTJtn1R3c+6h3L/6AevD6waC53 KDzqHioXHlmdlcMt49ADYRKl17ffF4HmO42f2yyEWdLxvvb1/maobyk4Y Qa2YCw0Yv/Kd+QqAUMIfSY7XAHo+X+jk0e3PFyxlpxJTA/zYA95gPdGW9 Ni7TvGiYAh3L/aOwEhUmaqEHpQ63Qxu/5PHv3yo/Xgx0K3A0JKJhsomIE spTW77D3YZyYt0dOnseX7Za+lu9O0uCLyu8P5NEmtv2/Z5nBE2Lt83una A==; X-IronPort-AV: E=McAfee;i="6500,9779,10450"; a="295764431" X-IronPort-AV: E=Sophos;i="5.93,265,1654585200"; d="scan'208";a="295764431" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2022 05:12:52 -0700 X-IronPort-AV: E=Sophos;i="5.93,265,1654585200"; d="scan'208";a="640034953" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO [10.0.2.15]) ([10.252.50.209]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2022 05:12:40 -0700 Message-ID: Date: Fri, 26 Aug 2022 15:12:34 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.11.0 Subject: Re: [PATCH v3 16/18] perf sched: Fixes for thread safety analysis Content-Language: en-US To: Ian Rogers , 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_Almeida?= , 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 , =?UTF-8?Q?Martin_Li=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 References: <20220824153901.488576-1-irogers@google.com> <20220824153901.488576-17-irogers@google.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki In-Reply-To: <20220824153901.488576-17-irogers@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 24/08/22 18:38, Ian Rogers wrote: > 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 7e4006d6b8bc..b483ff0d432e 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); I think you still need to wait for the threads to exit before destroying the mutexes. > return 0; > } >