Re: [patch net-next v4 0/4] return offloaded stats as default and expose original sw stats

Jiri Pirko
2016-06-17T15:42:47Z

Fri, Jun 17, 2016 at 05:35:53PM CEST, dsa@cumulusnetworks.com wrote:
>On 6/17/16 8:54 AM, Jamal Hadi Salim wrote:
>>On 16-06-17 10:05 AM, Jiri Pirko wrote:
>>>Fri, Jun 17, 2016 at 03:48:35PM CEST, dsa@cumulusnetworks.com wrote:
>>>>On 6/17/16 2:24 AM, Jiri Pirko wrote:
>>>>>
>>
>>>
>>>That is problematic. Existing apps depend on rtnetlink stats. But if we
>>>don't count offloaded forwarded packets, the apps don't see anything.
>>>Therefore I believe that this patchset approach is better. The existing
>>>apps continue to work and future apps can use newly introduces sw_stats
>>>to query slowpath traffic. Makes sense to me.
>>>
>>
>>I agree with Jiri. It is a bad idea to depend on ethtool for any of
>>this stuff. Is there a way we can tag netlink stats instead
>>to indicate they are hardware or software?
>
>Right, old API but the key here is that low level h/w stats are returned by a
>different API.
>
>By default ip, ifconfig, snmpd, etc all continue to get traditional S/W stats
>- counters as seen by the CPU.

Yep. And I believe that for offloaded forwarding, this tools should see
hw counters, as they show what is going on in real.