Re: Accuracy of rte_get_tsc_hz() compared to linux

[Isaac Boukris <iboukris@gmail.com>]

On Fri, Sep 20, 2024 at 5:36 PM Stephen Hemminger
<stephen@networkplumber.org> wrote:
>
> On Fri, 20 Sep 2024 09:26:05 +0200
> David Marchand <david.marchand@redhat.com> wrote:
>
> > On Fri, Sep 20, 2024 at 12:22 AM Stephen Hemminger
> > <stephen@networkplumber.org> wrote:
> > > Sigh. exposing tsc frequency through sysfs is a Redhat extension
> > > that never got merged upstream.
> >
> > Counter sight :-).
> >
> > Not sure where this assertion comes from.
> > I see no trace of this downstream: RH policy is "upstream first".
> >
>
> I missed the driver stuff in original mail and assumed that
> since it wasn't in upstream (or Debian) that it came from Redhat. Sorry.
>
> It would be good if kernel exposed it, and there was a proposal
> to do that, but it seemed to die from "no one should ever need or care about that"
>
> https://lwn.net/Articles/388263/
>

Too bad it wasn't merged, the tsc_mult and tsc_shift would have been
even better than tsc_khz itself, we could've implemented an even more
efficient cycles_ts_ns.I don't get what is the point of making rdtsc
available in userspace without this.