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