Re: Leveraging PTM

On Wed, Sep 6, 2023 at 10:33 PM Miroslav Lichvar <[email protected]>
wrote:

> On Mon, Sep 04, 2023 at 10:29:28AM +0200, Miroslav Lichvar wrote:
> > On Mon, Sep 04, 2023 at 01:34:48PM +0700, James Clark wrote:
> > > The  IES3110-8TF-R web UI has some configuration options that suggest
> it
> > > supports unicast.
>


> Ok, I got the switch and I can confirm it modifies the correction
> field in NTP-over-PTP messages as a one-step transparent clock.
>
> I did a quick test with two I210 NICs in a single machine connected to
> the switch. I tried few different pairs of ports. With the worst one
> and unmodified chronyd I see an asymmetry of about 25 ns and jitter of
> about 140 ns. When I apply the PTP correction the asymmetry disappears
> and jitter drops to 10 ns.
>
> Here is a plot of the raw offset from the measurements log:
> https://i.imgur.com/S6iywgH.png


I am happy to hear this works. That's an impressive graph.

I'm attaching the patch if you want to test it.
>

Thanks!

I'm curious about how well this works when there are multiple switches
between server/client. I've got two slightly different variants of this
switch, so I could potentially test this.

James