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From: Thomas Gleixner <tglx@linutronix.de>
To: Mac Lin <mkl0301@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>,
	John Stultz <john.stultz@linaro.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: Random abnormal high CPU sys usage related to timer
Date: Mon, 29 Aug 2016 12:45:18 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.20.1608291244470.5714@nanos> (raw)
In-Reply-To: <CAK1hUK_eZ9UubbiTaXwvwN0Q9eyVohrkVZ+Lz+1tCnQqHXjNig@mail.gmail.com>

On Sat, 27 Aug 2016, Mac Lin wrote:
> Hi Vegard,
> Thanks for the prompt response.
> The commit is introduced since 4.6, but the issue can be reproduced at
> 3.10 (earliest I have ever test). And testing on buildroot+4.7 with
> the commit reverted, the issue still happen.
> 
> In fact, I did a test that ran a script that keep increase a counter
> for 10 seconds on the same CPU. If I ran 2 of it, the number is half
> of running 1. But if I ran it while the issue happened, the counter
> reported is around the same value as the 1 process case. So I doubt
> that it might be an issue of reported number.
> 
> Is there other way to ensure the CPU is "really" doing something?

Tracing will tell you exactly what's going on in the system.

Thanks,

	tglx

  reply	other threads:[~2016-08-29 10:47 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-26 17:10 Mac Lin
2016-08-26 21:12 ` Vegard Nossum
2016-08-27 15:13   ` Mac Lin
2016-08-29 10:45     ` Thomas Gleixner [this message]
2016-08-29 16:26       ` Mac Lin

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