• Vinicius Costa Gomes's avatar
    tc: Add support for configuring the taprio scheduler · 5a781ccb
    Vinicius Costa Gomes authored
    This traffic scheduler allows traffic classes states (transmission
    allowed/not allowed, in the simplest case) to be scheduled, according
    to a pre-generated time sequence. This is the basis of the IEEE
    802.1Qbv specification.
    
    Example configuration:
    
    tc qdisc replace dev enp3s0 parent root handle 100 taprio \
              num_tc 3 \
    	  map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \
    	  queues 1@0 1@1 2@2 \
    	  base-time 1528743495910289987 \
    	  sched-entry S 01 300000 \
    	  sched-entry S 02 300000 \
    	  sched-entry S 04 300000 \
    	  clockid CLOCK_TAI
    
    The configuration format is similar to mqprio. The main difference is
    the presence of a schedule, built by multiple "sched-entry"
    definitions, each entry has the following format:
    
         sched-entry <CMD> <GATE MASK> <INTERVAL>
    
    The only supported <CMD> is "S", which means "SetGateStates",
    following the IEEE 802.1Qbv-2015 definition (Table 8-6). <GATE MASK>
    is a bitmask where each bit is a associated with a traffic class, so
    bit 0 (the least significant bit) being "on" means that traffic class
    0 is "active" for that schedule entry. <INTERVAL> is a time duration
    in nanoseconds that specifies for how long that state defined by <CMD>
    and <GATE MASK> should be held before moving to the next entry.
    
    This schedule is circular, that is, after the last entry is executed
    it starts from the first one, indefinitely.
    
    The other parameters can be defined as follows:
    
     - base-time: specifies the instant when the schedule starts, if
      'base-time' is a time in the past, the schedule will start at
    
     	      base-time + (N * cycle-time)
    
       where N is the smallest integer so the resulting time is greater
       than "now", and "cycle-time" is the sum of all the intervals of the
       entries in the schedule;
    
     - clockid: specifies the reference clock to be used;
    
    The parameters should be similar to what the IEEE 802.1Q family of
    specification defines.
    Signed-off-by: default avatarVinicius Costa Gomes <vinicius.gomes@intel.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    5a781ccb
sch_taprio.c 22.4 KB