RE: [PATCH net-next 06/11] net: fec: transmit XDP frames in bulk

[Wei Fang]

> On Tue, Jan 13, 2026 at 11:29:34AM +0800, Wei Fang wrote:
> > Currently, the driver writes the ENET_TDAR register for every XDP frame
> > to trigger transmit start. Frequent MMIO writes consume more CPU cycles
> > and may reduce XDP TX performance, so transmit XDP frames in bulk.
> >
> > Signed-off-by: Wei Fang <wei.fang@xxxxxxx>
> > ---
> 
> Did you test light loading case? Any unexpected latency happen? sometime
> missing trigger is hard to find when heavy loading.
> 

I don't think a missing trigger event will occur. The driver doesn't wait until
the number of packets reaches a certain threshold before triggering the
transmission. The driver receives some packets in each batch, the number
is not fixed, but there is a threshold. After putting these packets on the TX
BD ring, transmission is triggered. Therefore, each batch will definitely trigger
transmission.