• Jon Maloy's avatar
    tipc: improve link resiliency when rps is activated · 8d6e79d3
    Jon Maloy authored
    Currently, the TIPC RPS dissector is based only on the incoming packets'
    source node address, hence steering all traffic from a node to the same
    core. We have seen that this makes the links vulnerable to starvation
    and unnecessary resets when we turn down the link tolerance to very low
    values.
    
    To reduce the risk of this happening, we exempt probe and probe replies
    packets from the convergence to one core per source node. Instead, we do
    the opposite, - we try to diverge those packets across as many cores as
    possible, by randomizing the flow selector key.
    
    To make such packets identifiable to the dissector, we add a new
    'is_keepalive' bit to word 0 of the LINK_PROTOCOL header. This bit is
    set both for PROBE and PROBE_REPLY messages, and only for those.
    
    It should be noted that these packets are not part of any flow anyway,
    and only constitute a minuscule fraction of all packets sent across a
    link. Hence, there is no risk that this will affect overall performance.
    Acked-by: default avatarYing Xue <ying.xue@windriver.com>
    Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    8d6e79d3
flow_dissector.c 36 KB