On Sun, Jun 21, 2020 at 04:55:56PM +0100, Stuart Henderson wrote:
> On 2020/06/21 18:46, Paul Irofti wrote:
> > 
> > 
> > În 21 iunie 2020 16:30:43 EEST, Theo de Raadt <dera...@openbsd.org> a scris:
> > >Paul Irofti <p...@irofti.net> wrote:
> > >
> > >> If you change the name to rdtsc_ordered(), OK.
> > >
> > >That is a weaker name.
> > >
> > >Ordered in what way, at what level; ordered against what?
> > >
> > >This is using a specific pipeline ordering known as lfence.
> > >So it might as well say lfence.  That is the technical name for
> > >that type of ordering.  Being vague is unhelpful.
> > 
> > 
> > Ok then, if you think that's best.
> > 
> 
> Any idea why in
> https://www.intel.com/content/www/us/en/embedded/training/ia-32-ia-64-benchmark-code-execution-paper.html
> they are using cpuid to serialize access instead of lfence?

If I remember correctly it is because it is also a serializing
instruction, but nowadays it is more expensive than lfence.

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