From: Ido Schimmel <ido...@mellanox.com> Date: Sun, 5 Aug 2018 09:03:05 +0300
> Petr says: > > Due to an issue in Spectrum chips, when unicast traffic shares the same > queue as BUM traffic, and there is a congestion, the BUM traffic is > admitted to the queue anyway, thus pushing out all UC traffic. In order > to give unicast traffic precedence over BUM traffic, configure > multicast-aware mode on all ports. > > Under multicast-aware regime, when assigning traffic class to a packet, > the switch doesn't merely take the value prescribed by the QTCT > register. For BUM traffic, it instead assigns that value plus 8. That > limits the number of available TCs, but since mlxsw currently only uses > the lower eight anyway, it is no real loss. > > The two TCs (UC and MC one) are then mapped to the same subgroup and > strictly prioritized so that UC traffic is preferred in case of > congestion. > > In patch #1, introduce a new register, QTCTM, which enables the > multicast-aware mode. > > In patch #2, fix a typo in related code. > > In patch #3, set up TCs and QTCTM to enable multicast-aware mode. Series applied, thanks.
