On Tue, 17 Nov 2020 01:00:53 +0200 Vladimir Oltean wrote: > On Mon, Nov 16, 2020 at 02:35:44PM -0800, Jakub Kicinski wrote: > > On Tue, 17 Nov 2020 00:21:46 +0200 Vladimir Oltean wrote: > > > On Mon, Nov 16, 2020 at 01:34:53PM -0800, Jakub Kicinski wrote: > > > > You must expose relevant statistics via the normal get_stats64 NDO > > > > before you start dumping free form stuff in ethtool -S. > > > > > > Completely agree on the point, Jakub, but to be honest we don't give him > > > that possibility within the DSA framework today, see .ndo_get_stats64 in > > > net/dsa/slave.c which returns the generic dev_get_tstats64 implementation, > > > and not something that hooks into the hardware counters, or into the > > > driver at all, for that matter. > > > > Simple matter of coding, right? I don't see a problem. > > > > Also I only mentioned .ndo_get_stats64, but now we also have stats in > > ethtool->get_pause_stats. > > Yes, sure we can do that. The pause stats and packet counter ops would > need to be exposed to the drivers by DSA first, though. Not sure if this > is something you expect Oleksij to do or if we could pick that up separately > afterwards. Well, I feel like unless we draw the line nobody will have the incentive to do the work. I don't mind if it's Oleksij or anyone else doing the plumbing work, but the task itself seems rather trivial. > > > But it's good that you raise the point, I was thinking too that we > > > should do better in terms of keeping the software counters in sync with > > > the hardware. But what would be a good reference for keeping statistics > > > on an offloaded interface? Is it ok to just populate the netdev counters > > > based on the hardware statistics? > > > > IIRC the stats on the interface should be a sum of forwarded in software > > and in hardware. Which in practice means interface HW stats are okay, > > given eventually both forwarding types end up in the HW interface > > (/MAC block). > > A sum? Wouldn't that count the packets sent/received by the stack twice? Note that I said _forwarded_. Frames are either forwarded by the HW or SW (former never hit the CPU, while the latter do hit the CPU or originate from it).
