RE: [EXT] Re: [PATCH v2 RFC net-next 08/18] net: mvpp2: add FCA periodic timer configurations

Stefan Chulski
2021-01-24T14:44:46Z

>
> ----------------------------------------------------------------------
> On Sun, Jan 24, 2021 at 01:43:57PM +0200, stefanc@marvell.com wrote:
> > +/* Set Flow Control timer x140 faster than pause quanta to ensure
> > +that link
> > + * partner won't send taffic if port in XOFF mode.
>
> Can you explain more why 140 times faster is desirable here? Why 140 times
> and not, say, 10 times faster? Where does this figure come from, and what is
> the reasoning? Is there a switch that requires it?

I tested with 140.
Actually regarding to spec each quanta should be equal to 512 bit times.
In 10G bit time is 0.1ns.
So It actually should be:
FC_CLK_DIVIDER = 10000 / 512 = ~20. I took some buffer and made it 140.
So maybe I can do it 100?

Regards,
Stefan.