Poor performance on ER-X

Installing and Using OpenWrt
1

After my ER-X bricked itself, I decided to install OpenWRT (25.12.2), since Ubiquiti has basically abandoned EdgeMAX. I installed with no trouble via TFTP (I have a TTL-serial-USB cable), and everything seems to be working fine, except for a much slower internet connection. I'm only able to get about to get ~200 MBps up or down, whereas my actual connection is 500/500.
The only things I've changed is to add DNS servers, add some static DHCP leases, and enabling hardware flow offloading.
My hardware configuration isn't anything weird; fiber to the house, through the ISP box in bridge mode, then to my router.
With hardware flow off, the CPU load sits at about 0.1, and does not spike during bandwidth tests.
With hardware flow control off, the load sits at about 0.25-0.4, but it can only get to ~90 MBps (the CPU does not spike).

Really, I'm out of ideas. I don't see any resource constraints, and I know the hardware is perfectly capable of running 500/500, because it's been doing so for years. I could really use some suggestions!

eta: I checked the actual configuration. For some reason both software and hardware were enabled, so I turned off the software flow control:

# uci get firewall.@defaults[0].flow_offloading
1
# uci get firewall.@defaults[0].flow_offloading_hw
1
# uci set 'firewall.@defaults[0].flow_offloading=0'
2

It was supposed to do that: https://openwrt.org/docs/guide-user/perf_and_log/flow_offloading

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3

Well, the wiki strongly implies you only want one activated:

CLI with UCI (choose the one option you want)

But, it doesn't make any difference to anything. I should've mentioned that I've tried the various combinations.

4

Welp, pretty sure it's actually my ISP. I finally remembered step 0 for any troubleshooting, wherein you plug a computer directly into their ONT and see what happens. After a bit of a stare-down with their DHCP server, I got my laptop connected, and lo and behold, 200/200 instead of 500/500. Awesome.

I'm going to leave this open for the moment in case it turns out to not be the case. If I call them and they fix it, I'll put a large note at the top and close the thread then.

On the plus side, it looks like OpenWRT on the ER-X works really fast :slight_smile:

5

Sure enough, I'm an idiot :slight_smile: When briefly benched at fast.com and speedtest.net, it tested out at 500/500 MBps, while barely pulling CPU load above 0.33, . This might be a pretty great little combo, the ER-X hardware and OpenWRT! I've never liked this stupid thing, but never thought to try a brain transplant

To any future readers: Plug a notebook directly into your ISP modem or ONT, and check your speed there first. Blame your ISP before blaming your networking software/hardware. Don't be me.

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