Re: Aw: Re: Re: Re: [PATCH net] net: ethernet: mtk_eth_soc: fix tx throughput regression with direct 1G links

[Felix Fietkau <nbd@nbd.name>]

On 27.03.23 19:28, Frank Wunderlich wrote:
> 
>> Gesendet: Sonntag, 26. März 2023 um 22:09 Uhr
>> Von: "Felix Fietkau" <nbd@nbd.name>
>> On 26.03.23 19:49, Frank Wunderlich wrote:
>> >> Gesendet: Sonntag, 26. März 2023 um 19:27 Uhr
>> >> Von: "Felix Fietkau" <nbd@nbd.name>
> 
>> >> On 26.03.23 19:10, Frank Wunderlich wrote:
>> >> >> Gesendet: Sonntag, 26. März 2023 um 17:56 Uhr
>> >> >> Von: "Felix Fietkau" <nbd@nbd.name>
> 
>> >> >> On 25.03.23 10:28, Frank Wunderlich wrote:
>> >> >> >> Gesendet: Freitag, 24. März 2023 um 15:04 Uhr
>> >> >> >> Von: "Felix Fietkau" <nbd@nbd.name>
> 
>> >> >> > thx for the fix, as daniel already checked it on mt7986/bpi-r3 i tested bpi-r2/mt7623
>> >> >> > 
>> >> >> > but unfortunately it does not fix issue on bpi-r2 where the gmac0/mt7530 part is affected.
>> >> >> > 
>> >> >> > maybe it needs a special handling like you do for mt7621? maybe it is because the trgmii mode used on this path?
>> >> >> Could you please test if making it use the MT7621 codepath brings back 
>> >> >> performance? I don't have any MT7623 hardware for testing right now.
> 
>> > used the CONFIG_MACH_MT7623 (which is set in my config) boots up fine, but did not fix the 622Mbit-tx-issue
>> > 
>> > and i'm not sure i have tested it before...all ports of mt7531 are affected, not only wan (i remembered you asked for this)
>> Does the MAC that's connected to the switch use flow control? Can you 
>> test if changing that makes a difference?
> 
> it does use flow control/pause on mac and switch-port, disabled it, but it does not change anything (still ~620Mbit on tx)
> 
> +++ b/arch/arm/boot/dts/mt7623n-bananapi-bpi-r2.dts
> @@ -182,7 +182,7 @@ gmac0: mac@0 {
>                  fixed-link {
>                          speed = <1000>;
>                          full-duplex;
> -                       pause;
> +                       //pause;
>                  };
>          };
>   
> @@ -235,7 +235,7 @@ port@6 {
>                                          fixed-link {
>                                                  speed = <1000>;
>                                                  full-duplex;
> -                                               pause;
> +                                               //pause;
>                                          };
>                                  };
>                          };
> 
> regards Frank
I think I have an idea on how to properly deal with this issue now. I 
had overlooked the fact that on MT7623 the link to the switch is only 
1000M, so any QDMA shaping to that speed does not make any sense, since 
throughput is already limited by MAC speed.
I will make a patch that enables shaping only if port_speed < mac_speed.

- Felix