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 D4DFEC4332F for ; Thu, 10 Nov 2022 06:55:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229697AbiKJGzS (ORCPT ); Thu, 10 Nov 2022 01:55:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229514AbiKJGzR (ORCPT ); Thu, 10 Nov 2022 01:55:17 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6579F1570B; Wed, 9 Nov 2022 22:55:16 -0800 (PST) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4N7CJN3305zmVtX; Thu, 10 Nov 2022 14:55:00 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 10 Nov 2022 14:55:14 +0800 Received: from [10.174.178.55] (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 10 Nov 2022 14:55:14 +0800 Subject: Re: [PATCH v6 1/2] rcu: Add RCU stall diagnosis information To: Frederic Weisbecker CC: "Paul E . McKenney" , Neeraj Upadhyay , Josh Triplett , "Steven Rostedt" , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , , , Robert Elliott References: <20221109093739.187-1-thunder.leizhen@huawei.com> <20221109093739.187-2-thunder.leizhen@huawei.com> <20221109152017.GA298612@lothringen> From: "Leizhen (ThunderTown)" Message-ID: Date: Thu, 10 Nov 2022 14:55:13 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20221109152017.GA298612@lothringen> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On 2022/11/9 23:20, Frederic Weisbecker wrote: > On Wed, Nov 09, 2022 at 05:37:37PM +0800, Zhen Lei wrote: >> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c >> index ed93ddb8203d42c..e1ff23b2a14d71d 100644 >> --- a/kernel/rcu/tree.c >> +++ b/kernel/rcu/tree.c >> @@ -866,6 +866,23 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) >> rdp->rcu_iw_gp_seq = rnp->gp_seq; >> irq_work_queue_on(&rdp->rcu_iw, rdp->cpu); >> } >> + >> + if (rcu_cpu_stall_cputime && rdp->snap_record.gp_seq != rdp->gp_seq) { >> + u64 *cpustat; >> + struct rcu_snap_record *rsrp; >> + >> + cpustat = kcpustat_cpu(rdp->cpu).cpustat; >> + >> + rsrp = &rdp->snap_record; >> + rsrp->cputime_irq = cpustat[CPUTIME_IRQ]; >> + rsrp->cputime_softirq = cpustat[CPUTIME_SOFTIRQ]; >> + rsrp->cputime_system = cpustat[CPUTIME_SYSTEM]; > > You need to use kcpustat_field(), otherwise you'll get stalled values on nohz_full CPUs. OK, I'll update it. Thanks. > >> + rsrp->nr_hardirqs = kstat_cpu_irqs_sum(rdp->cpu); >> + rsrp->nr_softirqs = kstat_cpu_softirqs_sum(rdp->cpu); >> + rsrp->nr_csw = nr_context_switches_cpu(rdp->cpu); >> + rsrp->jiffies = jiffies; >> + rsrp->gp_seq = rdp->gp_seq; >> + } >> } >> >> return 0; >> diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h >> index 5653560573e22d6..7b6afb9c7b96dbe 100644 >> --- a/kernel/rcu/tree_stall.h >> +++ b/kernel/rcu/tree_stall.h >> @@ -428,6 +428,33 @@ static bool rcu_is_rcuc_kthread_starving(struct rcu_data *rdp, unsigned long *jp >> return j > 2 * HZ; >> } >> >> +static void print_cpu_stat_info(int cpu) >> +{ >> + u64 *cpustat; >> + struct rcu_snap_record *rsrp; >> + struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); >> + >> + if (!rcu_cpu_stall_cputime) >> + return; >> + >> + rsrp = &rdp->snap_record; >> + if (rsrp->gp_seq != rdp->gp_seq) >> + return; >> + >> + cpustat = kcpustat_cpu(cpu).cpustat; >> + >> + pr_err(" hardirqs softirqs csw/system\n"); >> + pr_err(" number: %8ld %10d %12lld\n", >> + kstat_cpu_irqs_sum(cpu) - rsrp->nr_hardirqs, >> + kstat_cpu_softirqs_sum(cpu) - rsrp->nr_softirqs, >> + nr_context_switches_cpu(cpu) - rsrp->nr_csw); >> + pr_err("cputime: %8lld %10lld %12lld ==> %lld(ms)\n", >> + div_u64(cpustat[CPUTIME_IRQ] - rsrp->cputime_irq, NSEC_PER_MSEC), >> + div_u64(cpustat[CPUTIME_SOFTIRQ] - rsrp->cputime_softirq, NSEC_PER_MSEC), >> + div_u64(cpustat[CPUTIME_SYSTEM] - rsrp->cputime_system, >> NSEC_PER_MSEC), > > Same here. OK > > Thanks. > . > -- Regards, Zhen Lei