On 01/25/2017 10:39 AM, Hayes Wang wrote:
Oliver Neukum [mailto:oneukum@xxxxxxxx]
Sent: Wednesday, January 25, 2017 5:35 PM
[...]
looking at r8152 I noticed that it uses NAPI. I never considered
this for the generic USB networking code as you cannot disable
interrupts for USB. Is it still worth it? What are the benefits?
You could use napi_gro_receive() and it influences the performance.
Another positive effect with NAPI is that you won't face out-of-order
ethernet frames as you get with non-NAPI drivers, e.g. ax88179_178a
http://marc.info/?l=linux-can&m=148049063812807&w=2
We have the issue with CAN drivers where all USB drivers and >90% of the
I/O mapped drivers do not use NAPI.
I wonder whether it makes sense to add NAPI to a driver which only has
ONE RX buffer ... but when searching for a solution for o-o-o frames I
was always pointed to NAPI.
Regards,
Oliver
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