On Fri, 27 Nov 2020 21:47:14 +0100 Andrew Lunn wrote: > > Is the periodic refresh really that awful? We're mostly talking error > > counters here so every second or every few seconds should be perfectly > > fine. > > Humm, i would prefer error counts to be more correct than anything > else. When debugging issues, you generally don't care how many packets > worked. It is how many failed you are interesting, and how that number > of failures increases. Right, but not sure I'd use the word "correct". Perhaps "immediately up to date"? High speed NICs usually go through a layer of firmware before they access the stats, IOW even if we always synchronously ask for the stats in the kernel - in practice a lot of NICs (most?) will return some form of cached information. > So long as these counters are still in ethtool -S, i guess it does not > matter. That i do trust to be accurate, and probably consistent across > the counters it returns. Not in the NIC designs I'm familiar with. But anyway - this only matters in some strict testing harness, right? Normal users will look at a stats after they noticed issues (so minutes / hours later) or at the very best they'll look at a graph, which will hardly require <1sec accuracy to when error occurred.
