[ovs-dev] [PATCH v14] Improved Packet Drop Statistics in OVS

[Eelco Chaudron]

On 5 Nov 2019, at 5:35, Anju Thomas wrote:

> Currently OVS maintains explicit packet drop/error counters only on 
> port level. Packets that are dropped as part of normal OpenFlow 
> processing are counted in flow stats of “drop” flows or as table 
> misses in table stats. These can only be interpreted by controllers 
> that know the semantics of the configured OpenFlow pipeline.
> Without that knowledge, it is impossible for an OVS user to obtain 
> e.g. the total number of packets dropped due to OpenFlow rules.
>
> Furthermore, there are numerous other reasons for which packets can be 
> dropped by OVS slow path that are not related to the OpenFlow 
> pipeline.
> The generated datapath flow entries include a drop action to avoid 
> further expensive upcalls to the slow path, but subsequent packets 
> dropped by the datapath are not accounted anywhere.
>
> Finally, the datapath itself drops packets in certain error 
> situations.
> Also, these drops are today not accounted for.This makes it difficult 
> for OVS users to monitor packet drop in an OVS instance and to alert a 
> management system in case of a unexpected increase of such drops.
> Also OVS trouble-shooters face difficulties in analysing packet drops.
>
> With this patch we implement following changes to address the issues 
> mentioned above.
>
> 1. Identify and account all the silent packet drop scenarios
>
> 2. Display these drops in ovs-appctl coverage/show
>
> Co-authored-by: Rohith Basavaraja <rohith.basavaraja at gmail.com>
> Co-authored-by: Keshav Gupta <keshugupta1 at gmail.com>
> Signed-off-by: Anju Thomas <anju.thomas at ericsson.com>
> Signed-off-by: Rohith Basavaraja <rohith.basavaraja at gmail.com>
> Signed-off-by: Keshav Gupta <keshugupta1 at gmail.com>

Thanks for following this trough! Did some quick sanity tests and based 
on my previous review of v13 and the diff to v14 it looks good to me!

Acked-by: Eelco Chaudron <echaudro at redhat.com>