stmmac: Performance regression after commit aff3d9eff843 "net: stmmac: enable multiple buffers"

[Joao Pinto]

Às 10:51 AM de 3/23/2017, Giuseppe CAVALLARO escreveu:
> On 3/23/2017 11:48 AM, Giuseppe CAVALLARO wrote:
>> Hello
>>
>> On 3/23/2017 11:20 AM, Corentin Labbe wrote:
>>>> I have a 4.21 QoS Core with 4 RX + 4 TX and detected no regression.
>>>> >Could you please share the iperf cmds you are using in order for me to
>>>> reproduce
>>>> >in my side?
>>
>> Joao, you have a really powerful HW integration with multiple channels for
>> both RX and TX.
>> Often this is not the same for other setup where, usually just a DMA0 is
>> present or, sometime, there
>> is just one RX extra channel.
>>
>> My question is, what happens on this kind of configurations? Are we still
>> guarantying the best performances?
>>
>> Also we have to guarantee, that the TSO and SG are always working. Another
>> point is the buffer sizes that
>> can be different among platforms.
>>
>> The problem  below reported by Corentin push me to think that there is a bug,
>> so we should
>> understand when this has been introduced and if likely fixed by some
>> configuration we are
>> not take care right now.
>>
>> ndesc_get_rx_status: Oversized frame spanned multiple buffers"
> 
> I wonder if this could be easily triggered by getting a big file via FTP. So not
> properly related on performance benchs

I am going to do that test and check it out and also run iperf a couple of
times. I am counting on doing this today and send you later the results. If
anyone gets results sooner please share.

> 
> peppe
> 
>>
>>
>> Best Regards
>> Peppe
>>
> 

Thanks.