On 12/16/20 3:09 PM, Ben Greear wrote:

Hello Eric,

The patch below evidently causes TCP throughput to be about 50Mbps instead of 700Mbps
when using ax200 to upload tcp traffic.

When I disable TSO, performance goes back up to around 700Mbps.

As a followup, when I revert the patch, upload speed goes to ~900Mbps,
so even better than just disabling TSO (I left TSO enabled after reverting the patch).

Thanks,
Ben

I recall ~5 years ago we had similar TCP related performance issues with ath10k.
I vaguely recall that there might be some driver-level socket pacing tuning value, but I cannot
find the right thing to search for.  Is this really a thing?  If so, maybe it will
be a way to resolve this issue?

See this more thorough bug report:

https://bugzilla.kernel.org/show_bug.cgi?id=209913

Patch description:
net: tso: add UDP segmentation support
Note that like TCP, we do not support additional encapsulations,
and that checksums must be offloaded to the NIC.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Thanks,
Ben