Re: [PATCH net-next] net: xilinx: axienet: Configure and report coalesce parameters in DMAengine flow

[Sean Anderson <sean.anderson@linux.dev>]

On 5/29/25 12:29, Andrew Lunn wrote:
>> Yeah, but the reason is that you are trading latency for throughput.
>> There is only one queue, so when the interface is saturated you will not
>> get good latency anyway (since latency-sensitive packets will get
>> head-of-line blocked). But when activity is sparse you can good latency
>> if there is no coalescing. So I think coalescing should only be used
>> when there is a lot of traffic. Hence why I only adjusted the settings
>> once I implemented DIM. I think you should be able to implement it by
>> calling net_dim from axienet_dma_rx_cb, but it will not be as efficient
>> without NAPI.
>> 
>> Actually, if you are looking into improving performance, I think lack of
>> NAPI is probably the biggest limitation with the dmaengine backend.
> 
> It latency is the goal, especially for mixing high and low priority
> traffic, having BQL implemented is also important. Does this driver
> have that?
> 
> 	Andrew

Yes, see commit c900e49d58eb ("net: xilinx: axienet: Implement BQL").

--Sean