Re: [PATCH net v2] r8152: avoid the driver drops a lot of packets

On Wed, 6 Sep 2023 11:11:48 +0800 Hayes Wang wrote:

Stop submitting rx, if the driver queue more than 256 packets.

If the hardware is more fast than the software, the driver would start
queuing the packets. And, the driver starts dropping the packets, if it
queues more than 1000 packets.

Increase the weight of NAPI could improve the situation. However, the
weight has been changed to 64, so we have to stop submitting rx when the
driver queues too many packets. Then, the device may send the pause frame
to slow down the receiving, when the FIFO of the device is full.

Good to see that you can repro the problem.

Before we tweak the heuristics let's make sure rx_bottom() behaves
correctly. Could you make sure that 
 - we don't perform _any_ rx processing when budget is 0
   (see the NAPI documentation under Documentation/networking)
 - finish the current aggregate even if budget run out, return
   work_done = budget in that case.
   With this change the rx_queue thing should be gone completely.
 - instead of copying the head use napi_get_frags() + napi_gro_frags() 
   it gives you an skb, you just attach the page to it as a frag and
   hand it back to GRO. This makes sure you never pull data into head
   rather than just headers.

Please share the performance results with those changes.
-- 
pw-bot: cr