Re: [PATCH 1/5] Add a global synchronization point for pvclock

Jeremy Fitzhardinge
2010-04-23T21:36:00Z

On 04/23/2010 02:31 PM, Zachary Amsden wrote:
> Does lfence / mfence actually serialize? I thought there was some
> great confusion about that not being the case on all AMD processors,
> and possibly not at all on Intel.
>
> A trap, however is a great way to serialize.
>
> I think, there is no serializing instruction which can be used from
> userspace which does not trap, at least, I don't know one off the top
> of my head.

rsm is not technically privileged... but not quite usable from usermode ;)

J