Re: Random abnormal high CPU sys usage related to timer

From	Thomas Gleixner <tglx@linutronix.de>
Newsgroups	linux.kernel
Subject	Re: Random abnormal high CPU sys usage related to timer
Date	2016-08-29 12:50 +0200
Message-ID	<sbsiB-6dl-3@gated-at.bofh.it> (permalink)
References	<sasXo-1xo-11@gated-at.bofh.it> <sawRj-3Y5-7@gated-at.bofh.it> <saNyO-6aa-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

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

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

Random abnormal high CPU sys usage related to timer Mac Lin <mkl0301@gmail.com> - 2016-08-26 19:20 +0200
  Re: Random abnormal high CPU sys usage related to timer Vegard Nossum <vegard.nossum@gmail.com> - 2016-08-26 23:30 +0200
    Re: Random abnormal high CPU sys usage related to timer Mac Lin <mkl0301@gmail.com> - 2016-08-27 17:20 +0200
      Re: Random abnormal high CPU sys usage related to timer Thomas Gleixner <tglx@linutronix.de> - 2016-08-29 12:50 +0200

csiph-web