• Matan Barak's avatar
    net/mlx4: Add A0 hybrid steering · d57febe1
    Matan Barak authored
    A0 hybrid steering is a form of high performance flow steering.
    By using this mode, mlx4 cards use a fast limited table based steering,
    in order to enable fast steering of unicast packets to a QP.
    
    In order to implement A0 hybrid steering we allocate resources
    from different zones:
    (1) General range
    (2) Special MAC-assigned QPs [RSS, Raw-Ethernet] each has its own region.
    
    When we create a rss QP or a raw ethernet (A0 steerable and BF ready) QP,
    we try hard to allocate the QP from range (2). Otherwise, we try hard not
    to allocate from this  range. However, when the system is pushed to its
    limits and one needs every resource, the allocator uses every region it can.
    
    Meaning, when we run out of raw-eth qps, the allocator allocates from the
    general range (and the special-A0 area is no longer active). If we run out
    of RSS qps, the mechanism tries to allocate from the raw-eth QP zone. If that
    is also exhausted, the allocator will allocate from the general range
    (and the A0 region is no longer active).
    
    Note that if a raw-eth qp is allocated from the general range, it attempts
    to allocate the range such that bits 6 and 7 (blueflame bits) in the
    QP number are not set.
    
    When the feature is used in SRIOV, the VF has to notify the PF what
    kind of QP attributes it needs. In order to do that, along with the
    "Eth QP blueflame" bit, we reserve a new "A0 steerable QP". According
    to the combination of these bits, the PF tries to allocate a suitable QP.
    
    In order to maintain backward compatibility (with older PFs), the PF
    notifies which QP attributes it supports via QUERY_FUNC_CAP command.
    Signed-off-by: default avatarMatan Barak <matanb@mellanox.com>
    Signed-off-by: default avatarOr Gerlitz <ogerlitz@mellanox.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    d57febe1
mlx4.h 40.1 KB