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Eric Dumazet authored
Commit 10f6dfcf (Revert "sch_netem: Remove classful functionality") reintroduced classful functionality to netem, but broke basic netem behavior : netem uses an t(ime)fifo queue, and store timestamps in skb->cb[] If qdisc is changed, time constraints are not respected and other qdisc can destroy skb->cb[] and block netem at dequeue time. Fix this by always using internal tfifo, and optionally attach a child qdisc to netem (or a tree of qdiscs) Example of use : DEV=eth3 tc qdisc del dev $DEV root tc qdisc add dev $DEV root handle 30: est 1sec 8sec netem delay 20ms 10ms tc qdisc add dev $DEV handle 40:0 parent 30:0 tbf \ burst 20480 limit 20480 mtu 1514 rate 32000bps qdisc netem 30: root refcnt 18 limit 1000 delay 20.0ms 10.0ms Sent 190792 bytes 413 pkt (dropped 0, overlimits 0 requeues 0) rate 18416bit 3pps backlog 0b 0p requeues 0 qdisc tbf 40: parent 30: rate 256000bit burst 20Kb/8 mpu 0b lat 0us Sent 190792 bytes 413 pkt (dropped 6, overlimits 10 requeues 0) backlog 0b 5p requeues 0 Signed-off-by:
Eric Dumazet <eric.dumazet@gmail.com> CC: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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