Content below is obsolete - and replaced with vpp test infra - ref. https://gerrit.fd.io/r/#/c/3345/ - patch is merged, closing this ticket.

CSIT functional tests need to push enough packets through the data plane to exercise the dual-loop code in data plane graph nodes.

Subject: Re: [csit-dev] [vpp-dev] Failure in CSIT testing of latest vpp-16.12-rc0~12-g3a83460
Date: Thu, 25 Aug 2016 15:52:25 +0000
From: Dave Barach (dbarach) <dbarach@cisco.com>
To: Peter Mikus -X (pmikus - PANTHEON TECHNOLOGIES at Cisco) <pmikus@cisco.com>, vpp-dev@lists.fd.io <vpp-dev@lists.fd.io>
CC: csit-dev@lists.fd.io <csit-dev@lists.fd.io>

We merged a patch earlier this morning which may have already fixed the problem. Please re-check before you spend a lot of time on it.

This morning’s patch fixed a dual-loop-only bug in the ipv6 stack. Over the last ten years, this has been a typical data-plane packet processing issue. “XYZ works perfectly, until the PPS rate hits 200 KPPS - 1 MPPS. Then something goes wrong.”

Even at the functional test level, we SHOULD exercise dual loops to ensure adequate code coverage. To do that, an absolute minimum vector size of 4 and a preferred vector size of around 10 is required.

Aside from using trex, the dpdk packet generator, or an ixia, there are a couple of ways to ensure non-trivial vector lengths. Use the built-in vpp packet generator. Fiddle with the indicated input nodes to build up a decent-sized vector before processing any of the vector elements.

It’s not an emergency, but we do need to do something about it at our earliest convenience.

Thanks… Dave