On Sun, 03 Jan 2021 10:20:11 -0800, Stephen Hemminger said: > You can use a qdisc that is a module, it just has to be available when device > is loaded. Typically that means putting it in initramfs.
Apparently, that's not *quite* true regarding the default qdisc, because I hit this situation (copying from another email): --- [/proc/sys/net] cat core/default_qdisc fq_codel [/proc/sys/net] tc -s qdisc show qdisc noqueue 0: dev lo root refcnt 2 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 qdisc pfifo_fast 0: dev eth0 root refcnt 2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 qdisc noqueue 0: dev wlan0 root refcnt 2 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 But if I give it a kick in the head... [/proc/sys/net] tc qdisc add dev wlan0 root fq_codel [/proc/sys/net] tc -s qdisc show dev wlan0 qdisc fq_codel 8001: root refcnt 2 limit 10240p flows 1024 quantum 1514 target 5ms interval 100ms memory_limit 32Mb ecn drop_batch 64 Sent 812 bytes 12 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 maxpacket 0 drop_overlimit 0 new_flow_count 0 ecn_mark 0 new_flows_len 0 old_flows_len 0 --- Note that wlan0 doesn't actually get plumbed up until after the initramfs has done its thing and we're quite late in the boot process and the /lib/modules on the production system is accessible, so it doesn't look like an implicit modprobe gets done in that case - fq_codel.ko was very much available when the device was brought up.
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