On Thu, 2016-04-14 at 17:34 +0200, Jiri Kosina wrote: > On Thu, 14 Apr 2016, Phil Sutter wrote: > > > OTOH some qdiscs (CBQ, DRR, DSMARK, HFSC, HTB, QFQ) assign the default > > one upon deletion instead of noop_qdisc, hence I would describe > > the situation using the words 'inconsistent' and 'accident' rather than > > 'expected'. :) > > Exactly. I'd again like to stress the fact that this configuration works: > > jikos:~ # tc qdisc show > qdisc tbf 10: dev eth0 root refcnt 2 rate 800Mbit burst 131000b lat > 1.0ms > > and this (after performing add/delete operation) doesn't: > > jikos:~ # tc qdisc show > qdisc tbf 10: dev eth0 root refcnt 2 rate 800Mbit burst 131000b lat > 1.0ms > > It's hard to spot a difference (hint: there is none).
This is because some qdisc are not visible in the dump. qdisc_list_add() uses a single list, so adding too much stuff in it could slow down fast path (qdisc_lookup(), called from qdisc_tree_reduce_backlog())
