root@OpenWrt:~# tc -s qdisc
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 mq 0: dev eth0 root
Sent 3811322278 bytes 3849958 pkt (dropped 0, overlimits 0 requeues 100)
backlog 0b 0p requeues 100
qdisc fq_codel 0: dev eth0 parent :4 limit 10240p flows 1024 quantum 1514 target 5ms interval 100ms memory_limit 4Mb ecn drop_batch 64
Sent 838023916 bytes 846824 pkt (dropped 0, overlimits 0 requeues 19)
backlog 0b 0p requeues 19
maxpacket 23264 drop_overlimit 0 new_flow_count 6637 ecn_mark 0
new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev eth0 parent :3 limit 10240p flows 1024 quantum 1514 target 5ms interval 100ms memory_limit 4Mb ecn drop_batch 64
Sent 1157865238 bytes 1140158 pkt (dropped 0, overlimits 0 requeues 24)
backlog 0b 0p requeues 24
maxpacket 26172 drop_overlimit 0 new_flow_count 9083 ecn_mark 0
new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev eth0 parent :2 limit 10240p flows 1024 quantum 1514 target 5ms interval 100ms memory_limit 4Mb ecn drop_batch 64
Sent 866540645 bytes 919412 pkt (dropped 0, overlimits 0 requeues 20)
backlog 0b 0p requeues 20
maxpacket 26172 drop_overlimit 0 new_flow_count 6199 ecn_mark 0
new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev eth0 parent :1 limit 10240p flows 1024 quantum 1514 target 5ms interval 100ms memory_limit 4Mb ecn drop_batch 64
Sent 948892479 bytes 943564 pkt (dropped 0, overlimits 0 requeues 37)
backlog 0b 0p requeues 37
maxpacket 26172 drop_overlimit 0 new_flow_count 6081 ecn_mark 0
new_flows_len 0 old_flows_len 0
qdisc noqueue 0: dev lan1 root refcnt 2
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
qdisc noqueue 0: dev lan2 root refcnt 2
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
qdisc noqueue 0: dev lan3 root refcnt 2
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
qdisc noqueue 0: dev lan4 root refcnt 2
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
qdisc noqueue 0: dev br-lan root refcnt 2
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
qdisc noqueue 0: dev br-wan root refcnt 2
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
root@OpenWrt:~#
OK, now the method.
Disable ingress part sqm by setting bw to 0
Set upload bw to half of achieved rate (28MBps) while upload fields are kilobit/s
28/4 = 14MB/s
14(MB/s)*8(b/B)*1024(M/k) = 114688kbps
Measure latency increase.
Now go with 3/4 7/8 etc and make a step back when added latency increases.
If download is now reasonable just leave it at zero.
Or repeat procedure with it.
Upload is good with no problems at it's full 30Mbit/s. Download has some issues. With SQM enabled and limited to ~200Mbit/s, there's no more increase. In 10% of all testings now it's maximum 5ms increase latency on download.
So i think CPU is the limiting factor. I was thinking about to install OpenWRT on my PC for testing. It has a Ryzen 5 5600X (6 Cores, slightly OC to 4.8GHz AllCore) which should handle this load of traffic, shouldn't it?
If i really get better results with openWRT on my PC, i have two options:
- buying/building a mini PC with a better CPU than the FritzBox
- -overclock CPU a little bit to get better performance on my FritzBox
You have to reduce DL bandwidth to avoid filling provider's line buffers.