Merge branch 'mlxsw-Enable-minimum-shaper-on-MC-TCs'
Ido Schimmel says: ==================== mlxsw: Enable minimum shaper on MC TCs Petr says: An MC-aware mode was introduced in commit 7b819530 ("mlxsw: spectrum: Configure MC-aware mode on mlxsw ports"). In MC-aware mode, BUM traffic gets a special treatment by being assigned to a separate set of traffic classes 8..15. Pairs of TCs 0 and 8, 1 and 9, etc., are then configured to strictly prioritize the lower-numbered ones. The intention is to prevent BUM traffic from flooding the switch and push out all UC traffic, which would otherwise happen, and instead give UC traffic precedence. However strictly prioritizing UC traffic has the effect that UC overload pushes out all BUM traffic, such as legitimate ARP queries. These packets are kept in queues for a while, but under sustained UC overload, their lifetime eventually expires and these packets are dropped. That is detrimental to network performance as well. In this patchset, MC TCs (8..15) are configured with minimum shaper of 200Mbps (a minimum permitted value) to allow a trickle of necessary control traffic to get through. First in patch #1, the QEEC register is extended with fields necessary to configure the minimum shaper. In patch #2, minimum shaper is enabled on TCs 8..15. In patches #3 and #4, first the MC-awareness test is tweaked to support the minimum shaper, and then a new test is introduced to test that MC traffic behaves well under UC overload. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
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