svn commit: r332447 - stable/11/sys/dev/ixgbe

[Stephen Hurd]

Yeah, I'm looking at the changes that caused this now.  Hopefully I'll have
this updated today.

On Thu, Apr 12, 2018 at 4:01 PM, Ryan Stone <rysto32 at gmail.com> wrote:

> Spinning in the kernel for a full second is a really bad idea.  At
> minimum this is going to hold off all callouts from one of the callout
> threads for up to a full second as ixgbe_local_timer() waits for the
> core mutex.  That chews up two CPU cores doing busy-wait loops (the
> ixgbe_stop() thread busy-waits in msec_delay and the callout thread
> adaptively spins waiting for the mutex).  If any other thread tries to
> acquire the core lock they also adaptively spin on the mutex chewing
> up yet more cores.  This includes any threads trying to fetch
> interface status (e.g. ifconfig), various interrupt handlers, etc.
>



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