Good Morning, So I've continued work on fixing the rk3328/rk3399 gmac mtu tx coe offload bug. I've found two fixes that maintain full performance and work consistently. First, is ayufan's tx coe patch [0], which takes the bugged_jumbo concept introduced in [1] and applies it to 1498 and above, vice 1500 and above. The only downside is this disables tx coe for full size packets, which has a negligible performance impact in my testing. The other option I've found that reliably works is bringing the mtu down to 1498. This allows tx coe to remain enabled, but with the downside of total loss of jumbo frames. The reduction in size has a negligible performance impact in my testing. I have also discovered that the rockchip implementation of the stmmac driver does not process flags such as max-frame-size. A third option, which I haven't explored because I don't know enough about how it works, is possibly tuning the axi settings, via the snps,axi-config and snps,mtl-tx-config handles. I don't know if this is feasible, but since tuning the dma settings affects the rk3328 I have hope. I do know that my current fix for the rk3328 does not provide full performance and does not work at all on the rk3399. Thoughts? [0] https://github.com/ayufan-rock64/linux-kernel/commit/8a41c672dd77e48b06c1b2dec3aa9db4bad30b49#diff-c897c0b53bd633240f4b12c4d29a5ff1 [1] https://github.com/torvalds/linux/commit/ebbb293f8b3021ae2009fcb7cb3b8a52fb5fd06a _______________________________________________ Linux-rockchip mailing list Linux-rockchip@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-rockchip
