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Date: Thu, 31 Aug 2017 15:37:09 +0200
From: Greg KH <greg@kroah.com>
To: Valentin Vidic <Valentin.Vidic@CARNet.hr>
Cc: stable@vger.kernel.org, Michael Lass <bevan@bi-co.net>
Subject: Re: Xen: decreasing cpu steal clock counter
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References: <20170831104451.e3ykmf66zbedg6iw@gavran.carpriv.carnet.hr>
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On Thu, Aug 31, 2017 at 12:44:51PM +0200, Valentin Vidic wrote:
> The following behavior of the steal counter observed
> in a Xen guest running 4.9 kernel:
> 
> $ while sleep 1; do head -1 /proc/stat ; done
> cpu  1556 0 1429 314195002 5529 0 64 14370419283 0 0
> cpu  1556 0 1429 314195402 5529 0 64 3601506907 0 0
> cpu  1556 0 1429 314195802 5529 0 64 1833790429262 0 0
> cpu  1556 0 1429 314196203 5529 0 64 1821957766874 0 0
> cpu  1556 0 1429 314196603 5529 0 64 1810766851628 0 0
> cpu  1556 0 1429 314197002 5529 0 64 1792853828090 0 0
> 
> Could this patch or some variation of it be included in
> the 4.9 LTS?

What patch?

> https://bugs.debian.org/cgi-bin/bugreport.cgi?att=1;bug=871608;filename=handle-decreasing-steal-clock.patch;msg=5
> 
> Problem exists in versions 4.8 until 4.11 so older LTS
> kernels should not be affected.
> 
> More details on this problem here:
> 
> https://0xstubs.org/debugging-a-flaky-cpu-steal-time-counter-on-a-paravirtualized-xen-guest/

What is the git commit id of the aptch in Linus's tree that resolves
this issue?

thanks,

greg k-h