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From: "Elliott, Robert (Servers)" <elliott@hpe.com>
To: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>,
	"paulmck@kernel.org" <paulmck@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
	Neeraj Upadhyay <quic_neeraju@quicinc.com>,
	Josh Triplett <josh@joshtriplett.org>,
	"Steven Rostedt" <rostedt@goodmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	"rcu@vger.kernel.org" <rcu@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v4 4/4] rcu: Add RCU stall diagnosis information
Date: Tue, 8 Nov 2022 19:29:34 +0000	[thread overview]
Message-ID: <MW5PR84MB18421BE7AC33B65B9414928DAB3F9@MW5PR84MB1842.NAMPRD84.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <e6f96a66-59e6-5889-a0f0-6451d8469c24@huawei.com>


> Maybe we should add another member to record jiffies.
> 
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index b33165dba1ea745..6d9c876ea5c85a6 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -880,6 +880,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data
> *rdp)
>                         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;

Yes, that works:

[  252.139108] tcrypt: rcu testing - kernel_fpu_disable for rude 22 s
[  255.140204] rcu: INFO: rcu_preempt self-detected stall on CPU 39
[  255.146438] rcu:     CPU 39-....: (2995 ticks this GP) idle=5014/1/0x4000000000000000 softirq=2373/2374 fqs=751
[  255.156512] rcu:     CPU 39          hardirqs   softirqs           csw     system  cond_resched
[  255.165182] rcu:     CPU 39   count:        0          3             0                        0
[  255.173853] rcu:     CPU 39 cputime:        3          0                     1493               ==> 1530 (ms)
[  255.183746] rcu:     CPU 39 current: in_kernel_fpu_begin=1 preemptible=0
[  255.190407] rcu:     CPU 39 self-detected stall t=3051 jiffies g=18181 q=373 ncpus=56
[  255.198205] CPU: 39 PID: 2607 Comm: modprobe Not tainted 6.0.0+ #14
...
[  264.450164] rcu: INFO: rcu_preempt self-detected stall on CPU 39
[  264.456416] rcu:     CPU 39-...k.: (12000 ticks this GP) idle=5014/1/0x4000000000000000 softirq=2373/2374 fqs=3006
[  264.466690] rcu:     CPU 39          hardirqs   softirqs           csw     system  cond_resched
[  264.475390] rcu:     CPU 39   count:        0         21             0                        0
[  264.484092] rcu:     CPU 39 cputime:      328          0                     8982               ==> 9293 (ms)
[  264.494015] rcu:     CPU 39 current: in_kernel_fpu_begin=1 preemptible=0
[  264.500706] rcu:     CPU 39 self-detected stall t=12361 jiffies g=18181 q=601 ncpus=56
[  264.508619] CPU: 39 PID: 2607 Comm: modprobe Not tainted 6.0.0+ #14
...
[  273.760124] rcu: INFO: rcu_preempt self-detected stall on CPU 39
[  273.766376] rcu:     CPU 39-....: (21004 ticks this GP) idle=5014/1/0x4000000000000000 softirq=2373/2374 fqs=5262
[  273.776649] rcu:     CPU 39          hardirqs   softirqs           csw     system  cond_resched
[  273.785348] rcu:     CPU 39   count:        0         17             0                        0
[  273.794050] rcu:     CPU 39 cputime:      328          0                     8981               ==> 9293 (ms)
[  273.803971] rcu:     CPU 39 current: in_kernel_fpu_begin=1 preemptible=0
[  273.810660] rcu:     CPU 39 self-detected stall t=21671 jiffies g=18181 q=1112 ncpus=56
[  273.818659] CPU: 39 PID: 2607 Comm: modprobe Not tainted 6.0.0+ #14



  reply	other threads:[~2022-11-08 19:30 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-04  2:12 [PATCH v4 0/4] " Zhen Lei
2022-11-04  2:12 ` [PATCH v4 1/4] genirq: Fix the return type of kstat_cpu_irqs_sum() Zhen Lei
2022-11-04  2:12 ` [PATCH v4 2/4] sched: Add helper kstat_cpu_softirqs_sum() Zhen Lei
2022-11-04  2:12 ` [PATCH v4 3/4] sched: Add helper nr_context_switches_cpu() Zhen Lei
2022-11-04  2:12 ` [PATCH v4 4/4] rcu: Add RCU stall diagnosis information Zhen Lei
2022-11-04  3:12   ` Leizhen (ThunderTown)
2022-11-04 13:43     ` Paul E. McKenney
2022-11-05  1:58   ` Elliott, Robert (Servers)
2022-11-05  7:03     ` Leizhen (ThunderTown)
2022-11-05 20:32       ` Paul E. McKenney
2022-11-07  3:20         ` Leizhen (ThunderTown)
2022-11-05 20:06     ` Paul E. McKenney
2022-11-07  2:10       ` Elliott, Robert (Servers)
2022-11-07 11:49         ` Leizhen (ThunderTown)
2022-11-07 20:38           ` Elliott, Robert (Servers)
2022-11-07 21:57             ` Elliott, Robert (Servers)
2022-11-08  3:06               ` Leizhen (ThunderTown)
2022-11-08  5:53                 ` Elliott, Robert (Servers)
2022-11-08  6:41                   ` Leizhen (ThunderTown)
2022-11-08 19:29                     ` Elliott, Robert (Servers) [this message]
2022-11-08  3:18             ` Leizhen (ThunderTown)

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