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From: Andi Kleen <ak@linux.intel.com>
To: paulmck@kernel.org, Chao Gao <chao.gao@intel.com>
Cc: Feng Tang <feng.tang@intel.com>,
	kernel test robot <oliver.sang@intel.com>,
	John Stultz <john.stultz@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Stephen Boyd <sboyd@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
	Mark Rutland <Mark.Rutland@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Xing Zhengjun <zhengjun.xing@linux.intel.com>,
	Chris Mason <clm@fb.com>, LKML <linux-kernel@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>,
	lkp@lists.01.org, lkp@intel.com, ying.huang@intel.com,
	zhengjun.xing@intel.com
Subject: Re: [clocksource] 8901ecc231: stress-ng.lockbus.ops_per_sec -9.5% regression
Date: Wed, 4 Aug 2021 21:34:13 -0700	[thread overview]
Message-ID: <a8d99be8-da3f-6c8e-cdbb-efd239ff3f14@linux.intel.com> (raw)
In-Reply-To: <20210805040349.GD4397@paulmck-ThinkPad-P17-Gen-1>


> My current thought is that if more than (say) 100 consecutive attempts
> to read the clocksource get hit with excessive delays, it is time to at
> least do a WARN_ON(), and maybe also time to disable the clocksource
> due to skew.  The reason is that if reading the clocksource -always-
> sees excessive delays, perhaps the clock driver or hardware is to blame.
>
> Thoughts?

On TDX this would be fatal because we don't have a usable fallback source

(just jiffies). Better try as hard as possible.


-Andi

>
> 			

  reply	other threads:[~2021-08-05  4:34 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-21  8:33 kernel test robot
2021-05-21 13:56 ` Paul E. McKenney
2021-05-22 16:08   ` Paul E. McKenney
2021-05-26  6:49     ` Feng Tang
2021-05-26 13:49       ` Paul E. McKenney
2021-05-27 18:29         ` Paul E. McKenney
2021-05-27 19:01           ` Andi Kleen
2021-05-27 19:19             ` Paul E. McKenney
2021-05-27 19:29               ` Matthew Wilcox
2021-05-27 21:05                 ` Paul E. McKenney
2021-05-28  0:58                   ` Andi Kleen
2021-06-01 17:10                     ` Paul E. McKenney
2021-08-02  6:20           ` Chao Gao
2021-08-02 17:02             ` Paul E. McKenney
2021-08-03  8:58               ` Chao Gao
2021-08-03 13:48                 ` Paul E. McKenney
2021-08-05  2:16                   ` Chao Gao
2021-08-05  4:03                     ` Paul E. McKenney
2021-08-05  4:34                       ` Andi Kleen [this message]
2021-08-05 15:33                         ` Paul E. McKenney
2021-08-05  5:39                       ` Chao Gao
2021-08-05 15:37                         ` Paul E. McKenney
2021-08-06  2:10                           ` Chao Gao
2021-08-06  4:15                             ` Paul E. McKenney

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