I'm not new to Openwrt but for the first time installed it on a slightly more capable router (if compared to the previous ones), tp-link archer c7.
I enabled sqm and... wow! What a difference!
I just want to say thanks to devs.
Still monitoring its behavior (plotting a couple of rrd graphs in Cacti) where my main concern is to see if it can handle traffic peaks in my home network (like son playing games, wife and me doing web conferences, netflix streaming, etc).
There is no issue, just a thank you devs post.
As for the monitoring thing, it is running smoothly, with one event worth mentioning. Yesterday my son downloaded a 12 GB game from one of those game frameworks I don't remember right now. There were connection hicups in the first minute, including loss of network connectivity. After it reconected, it took a minute or two until it maxed out bandwidth. From there on, the download proceeded and the graph was a flat line at max connection speed.
While downloading, Lua became unresponsive so I opened a ssh session, and top showed 0% idle.
In summary, this was the first time the router showed its cpu limitations, being sqm cpu intensive. Even so, after the first hicups, the download went just perfect.
Beside that, we've been using Internet on a moderate to heavy level, so, in the end, I guess this router model can still be considered appropriate to our needs.
I'm planning however to do another game download from that site to try to understand why this download put such a burden on the router, and the others didn't (including torrents)
EDIT: forgot to mention: the router is a tp-link archer c7 v5