OpenWRT 19.07 and bcm53xx target + flow offloading

So, seems like I found a solution which restores full wire speed for NAT for broadcom routers.

TLDR: turn off GRO.

More details here.
Apparently it is a regression triggered by missing hardware acceleration in bgmac driver.
Not sure why this is not fixed in the openwrt or Linux kernel still.

With the following changes this router becomes a beast:

  1. 'GRO off' (ethtool -K eth0 gro off) restores 1gpbs NAT
  2. Irqbalance moves wifi and switch irqs to different cores - CPU never overloads.
  3. New brcmfmac4366-pcie.bin driver (Mar 2020) allows for 160mhz channel (actually works)
  4. Tweaked latest regdb allows for txpower tweaks, dfs channels, and serves as a workaround for luci dfs problem.

Hope this helps.

P.s. seems like this router is now sold as QUANTUM DAX/WL-WN538A8 for $20-50 in bulk. A new cheap openwrt hit?

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