Hi Pim, your patch degrades performance of it’s primary use case which is emulating exact NIC behavior, same behavior you don’t like.
Do you really need slow, cpu intensive toeplitz calculation for your use case? Why not building dedicated code for that usecase which leverages much faster hardware crc32c? — Damjan > On 30.04.2026., at 19:52, Pim van Pelt via lists.fd.io > <[email protected]> wrote: > > Hoi folks, > > I bumped into my buddy Ian who is using VPP as a BNG for PPPoE sessions. He > explained that his NICs are not able to supply RSS for the PPPoE traffic, > which means in his case that all PPPoE sessions hash to a single Rx queue, > making VPP essentially single-threaded. We chatted about Soft RSS, but upon > closer inspection, it makes an implicit assumption that the L2 ethertype is > offset at N bytes from the start of the frame, and the only two supported > types are IPv4 0x0800 and IPv6 0x86DD. This means that PPPoE, ethertype > 0x8864, cannot be used with Soft RSS plugin. > > I've made a small change that allows the operator to specify precisely where > the IP header will start, using the first nybble there to determine if IPv4 > of IPv6 header follows, see https://gerrit.fd.io/r/c/vpp/+/45595 > > Now, PPPoE traffic can be configured using: > soft-rss config TenGitabitEthernet10/0/0 type 4-tuple ip-offset 30 threads > 16-19 > > This will capture the IP header at offset 30: > SRC-MAC(6)/DST-MAC(6)/OUTER-VLAN(4)/INNER-VLAN(4)/ETHERTYPE(2)/PPPoE-HEADER(6)/PPP-ID(2)/IP-HEADER > > I spent some time today with Ian to validate that with this patch, he can > indeed funnel PPPoE sessions to any number of workers, raising throughput > from ~5Mpps in a single threaded setup, to 30Mpps (the limit that one Rx > queue + SoftRSS offload can provide), which is a huge improvement. > > Please take a look at https://gerrit.fd.io/r/c/vpp/+/45595 which also adds an > API and a few Python tests for SoftRSS taking PPPoE as an example case. >
-=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#27005): https://lists.fd.io/g/vpp-dev/message/27005 Mute This Topic: https://lists.fd.io/mt/119085845/21656 Group Owner: [email protected] Unsubscribe: https://lists.fd.io/g/vpp-dev/leave/14379924/21656/631435203/xyzzy [[email protected]] -=-=-=-=-=-=-=-=-=-=-=-
