On Wed, Jul 30, 2025 at 08:39:25AM +0300, Gal Pressman wrote:
> On 30/07/2025 4:51, Jakub Kicinski wrote:
> > On Tue, 29 Jul 2025 19:07:59 +0100 Vadim Fedorenko wrote:
> >> On 29/07/2025 18:31, Andrew Lunn wrote:
> >>>> The only one bin will have negative value is the one to signal the end
> >>>> of the list of the bins, which is not actually put into netlink message.
> >>>> It actually better to change spec to have unsigned values, I believe.
> >>>
> >>> Can any of these NICs send runt packets? Can any send packets without
> >>> an ethernet header and FCS?
> >>>
> >>> Seems to me, the bin (0,0) is meaningless, so can could be considered
> >>> the end marker. You then have unsigned everywhere, keeping it KISS.
> >>
> >> I had to revisit the 802.3df-2024, and it looks like you are right:
> >> "FEC_codeword_error_bin_i, where i=1 to 15, are optional 32-bit
> >> counters. While align_status is true, for each codeword received with
> >> exactly i correctable 10-bit symbols"
> >>
> >> That means bin (0,0) doesn't exist according to standard, so we can use
> >> it as a marker even though some vendors provide this bin as part of
> >> histogram.
> >
> > IDK, 0,0 means all symbols were completely correct.
> > It may be useful for calculating bit error rate?
>
> Exactly. mlx5 will use (0, 0) for sure.
Sorry, i did not spend time to read the standard and issued this was
related to frame length somehow, like the RMON statistics which have
bins for packet length counts.
Andrew
