Στις Κυρ, 10 Μαρ, 2019 at 2:26 ΠΜ, ο/η "Leonidas P.
Papadakos" <papadakospan@xxxxxxxxx> έγραψε:
> > We have several issues on the rk3328.
> >
> > The first issue, which you describe as the ssh lag, is the
> > tx-offload issue.
> > Packets that are larger than the MTU and will be fragmented
break if
> > tx-offload is enabled.
> > To fix this, you must somehow disable tx-offload.
> > force-thresh-dma-mode disabled tx-offload, but had other side
effects.
> > Ayufan's patch disables tx-offload only if the packet is larger
than
> > 1498.
> > You can also disable tx-offload from userspace with ethtool.
> >
> > The second issue is the high rate of tx packets being corrupted,
> > which my patch to set the tx pull values fixes.
> >
> > The third issue is the tx and rx delays need to be tuned now
that
> > the tx packet corruption issue has been fixed.
> >
> > I hope this clears things up a little for you.
>
> Yup, that's what I have in my mind already. My previous comment
wasn't
> clear, I know.
> I pieced it together after your dma-mode patch, because that one
fixed
> the ssh lag.
> My previous email was just what I saw after those changes.
>
> In my case the link reset still happens with your patch.
>
> You're thinking that the combination of your patch, ayufan's
> "conditional" patch and a specific tweak in the delays would work
for
> the network instability problem?
>
Correct, the link-reset tends to happen when the delays are at the
edge of
working.
There is also the possibility that board level manufacturing
tolerances are
causing issues where the delay can change between boards.
If this is the case, we will have to make an auto-tune function,
probably
based off the mmc version.
So, I tried just your patch with archlinuxARM linux 5.0
(meaning the tx/rx_delays are 0x25/0x11 respectively if I'm not
mistaken)
and disabled tx offload through ethtool.
After 3 30-second iperf3 tests, no link resets! I get about the same
speed you mentioned before,
800-something to 700-something lowest.
Seems like the delays that are already there in the dts are better
than the ones I picked up from the Armbian dts.
It's worth noting that I've never noticed a link reset in my ~3
months of using the 4.4 Rockchip kernel
that Armbian packages using ayufan's linux-kernel repo. Maybe
something there?
All in all, it does seem to be much better with your patch.
I've been trying to reach ayufan about his patch, getting is into
mainline:
https://github.com/ayufan-rock64/linux-mainline-kernel/commit/41eeb7cd789ea7cac0cbf4b35b53055f354da757
but it seems he's not responding. I'll cc him.
His patch would be a really cool fix if it could be in 5.1, or even 5.2,
as a replacement to force_thresh_dma_mode
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