Jakub Kicinski [off-list ref] writes:

On Mon, 29 Nov 2021 18:08:12 +0100 Petr Machata wrote:

quoted

For those who care to know about the offloaded datapath, it would be
nice to have the option to request either just the SW stats, or just the
HW stats. A logical place to put these would be under the OFFLOAD_XSTATS
nest of the RTM_GETSTATS message, but maybe the SW ones should be up
there next to IFLA_STATS_LINK_64. (After all it's going to be
independent from not only offload datapath, but also XDP.)

What I'm getting at is that I thought IFLA_OFFLOAD_XSTATS_CPU_HIT
should be sufficient from uAPI perspective in terms of reporting.
User space can do the simple math to calculate the "SW stats" if 
it wants to. We may well be talking about the same thing, so maybe
let's wait for the code?

Ha, OK, now I understand. Yeah, CPU_HIT actually does fit the bill for
the traffic that took place in SW. We can reuse it.

I still think it would be better to report HW_STATS explicitly as well
though. One reason is simply convenience. The other is that OK, now we
have SW stats, and XDP stats, and total stats, and I (as a client) don't
necessarily know how it all fits together. But the contract for HW_STATS
is very clear.