[ovs-discuss] Inaccurate statistics in flow_removed struct using OpenvSwitch

Ethan Jackson ethan at nicira.com
Wed May 18 19:55:42 UTC 2011

> Looking at the code, ovs-openflowd returns facet + stat as packet
> count for the flow removed.  The number recorded by facet is correct,
> but the sum of the value exceed the real value.  This occurs at the
> facet_update_stats function.  What is the purpose of the addition?
> Can we expect accurate statistics from OVS?

I should have responded to this question in my previous email.  Packet
statistics are recorded in a best-effort fashion.  In general they
should be accurate, but there is no hard guarantee that they are
especially in certain edge cases involving complex flow tables
including resubmit actions.  In short, you should expect accurate
statistics from OVS noting the aforementioned caveat.

Thanks again for reporting this bug.

More information about the discuss mailing list