This bug is awaiting verification that the kernel in -proposed solves
the problem. Please test the kernel and update this bug with the
results. If the problem is solved, change the tag 'verification-needed-
yakkety' to 'verification-done-yakkety'. If the problem still exists,
change the tag 'verification-needed-yakkety' to 'verification-failed-

If verification is not done by 5 working days from today, this fix will
be dropped from the source code, and this bug will be closed.

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** Tags added: verification-needed-yakkety

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  h-prod does not function across cores

Status in linux package in Ubuntu:
  Fix Released
Status in linux source package in Yakkety:
  Fix Committed
Status in linux source package in Zesty:
  Fix Released

Bug description:
  There is a  performance problem issue with h-prod. I can see that
  h-prod calls are only waking hardware threads from a h-cede call when
  the caller is on the same core as the thread being awoken (sibling
  theads).  For cross core prods the target thread remains in h-cede
  until its next decrementer interrupt.  That is causing guest OS some
  significant dispatching delays.

   The fix is now upstream as commit 8464c8842de2 ("KVM: PPC: Book3S HV:
  Fix H_PROD to actually wake the target vcpu", 2016-12-06) in

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