Hi, I have an Edgerouter-X with 18.06.5 with 200/80 Mbits/s @ Fiber over PPPoE.
I setup SQM using Cake + Piece of Cake, 175/70 Mbits/s, Ethernet with 44 of packet for overheading, all over PPPoE-wan interface (my ISP does not use VLAN for voip or tv).
In speedtest I can't get more than 130Mbits/s. I dunno if I should set a little bit less packets for overheading, or change something in setup.
Plus, I didn't change MTU on PPPoE interface. running some MTU test, I can afford 1464 (which means, I can handle 1492 bytes, am I right?)
The main reason I'm setting up this, is to lower the bufferbloat when some parent is downloading hard. Plus, my ISP seems to be incapable to handle the traffic over high intensity, giving me some packet loss, etc.
My main use is competitive gaming, lower latency + stability is the intention.
Nah theoretically the maximum you could be able to see from your settings is around: 175 * (1500-8-20-20)/(1500-8+44) = 165.4296875 Mbps
maybe a bit less if you use rfc1323 timestamps, but I believe you only see ~130 Mbps, as your router simply runs out of CPU cycles. You could test this by logging into the router over ssh while running a long speedtest and look at the idle% reported in the top row(s) of top -d 1. If that drops to <= 5% you most likely are CPU bound.
So I believe playing around with the overhead is not going to give you much...
On PPPoE MTU often is 1500, but the PPPoE header costs 8 bytes and the remote PPPoE-tunnel side will remove the PPPoE header before passng packets into the wider internet, that is quite normal. typically that corresponds to a MSS of 1500-8-20-20 = 1452 B, so 1464 sounds odd, but feel free to copy and paste the contents of the "Share Your Results" box on https://www.speedguide.net/analyzer.php.
I'll check about %idle, but I don't think it's the problem. Edgerouter-X has 2 cores at 880MHz.
About PPPoE question, I said 1464 after use: http://www.letmecheck.it/mtu-test.php
So, 1464 B is the max I can receive with no fragmentation. 1464 + 28 (for ICMP, etc.) = 1492 B (the normal value we can see all around in PPPoE cases)
Anyway, I didn't force any MTU value on PPPoE Interface. It's unchanged (1500, by default, I guess).
I talked about MSS, and I talked about MTU.
I'll ready carefully the "sing and dance" you've posted. But I'd like to add: My ISP burst the connection at begginning. So, I have 200 Mbps of download speed, at the start of any downloading, or speedtesting, the speed reaches 500~600 Mbps and comes lowering until stabilize at 200. With QoS, or SQM, the graphic of the speed x time is more linear. At beginning the download starts growing until reach 200 and stabilize.
About my ISP cant handle high traffic, I know I can't do nothing unless argue with 'em.
I really appreciate your reply. Thanks!
P.S.: I dunno how to multi quote using this forum interface.
But that, less achieved bandwidth than configured is typically a strong indicator of a maxed out CPU. But again that is easy to test. Just as side-note the ~800 MHz Mips CPU's in the edgerouter X are really not as powerful as one would wish...