From: Willem de Bruijn <[email protected]> Date: Thu, 23 May 2019 13:48:46 -0400
> From: Willem de Bruijn <[email protected]> > > The SO_TXTIME API enables packet tranmission with delayed delivery. > This is currently supported by the ETF and FQ packet schedulers. > > Evaluate the interface with both schedulers. Install the scheduler > and send a variety of packets streams: without delay, with one > delayed packet, with multiple ordered delays and with reordering. > Verify that packets are released by the scheduler in expected order. > > The ETF qdisc requires a timestamp in the future on every packet. It > needs a delay on the qdisc else the packet is dropped on dequeue for > having a delivery time in the past. The test value is experimentally > derived. ETF requires clock_id CLOCK_TAI. It checks this base and > drops for non-conformance. > > The FQ qdisc expects clock_id CLOCK_MONOTONIC, the base used by TCP > as of commit fb420d5d91c1 ("tcp/fq: move back to CLOCK_MONOTONIC"). > Within a flow there is an expecation of ordered delivery, as shown by > delivery times of test 4. The FQ qdisc does not require all packets to > have timestamps and does not drop for non-conformance. > > The large (msec) delays are chosen to avoid flakiness. ... > Changes v1->v2: update commit message output > > Signed-off-by: Willem de Bruijn <[email protected]> > Acked-by: Eric Dumazet <[email protected]> Applied, thanks Willem.
