Re: stmmac / meson8b-dwmac

From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
To: ingrassia@epigenesys.com, Gpeppe.cavallaro@st.com,
	alexandre.torgue@st.com
Cc: Simon Huelck <simonmail@gmx.de>,
	linux-amlogic@lists.infradead.org, netdev@vger.kernel.org
Subject: Re: stmmac / meson8b-dwmac
Date: Mon, 4 Feb 2019 15:34:41 +0100	[thread overview]
Message-ID: <CAFBinCAkXN42piiYsc_Qmuqv0w4dbK86gq10AbZyrB-zKuh9hg@mail.gmail.com> (raw)
In-Reply-To: <e05b7448-cd95-cdeb-c88d-3a324d5f1ddc@gmx.de>

On Thu, Jan 17, 2019 at 10:23 PM Simon Huelck <simonmail@gmx.de> wrote:
[...]
> >> I got problems with my ODROID c2 running on 4.19.16 ( and some releases
> >> earlier ). the stmmac / dwmac driver doesnt provide the 800M/900M
> >> performance that i was used to earlier.
> >>
> >>
> >> Now im stuck near 550M/600M in the same environment. but what really
> >> confuses me that duplex does hurt even more.
> > interesting that you see this on the Odroid-C2 as well.
> > previously I have only observed it on an Odroid-C1
> >
> >> PC --- VLAN3 --> switch --VLAN3--> ODROID
> >>
> >> NAS <-- VLAN1 -- switch <-- VLAN1-- ODROID
> >>
> >>
> >> this means when im doing a iperf from PC to NAS, that my ODROID has load
> >> on RX/TX same time (duplex). this shouldnt be an issue , all is 1GBits
> >> FD. And in the past that wasnt an issue.
+Cc Emiliano who has seen a similar duplex issue on his Odroid-C1: [0]
(please note that all kernels prior to v5.1 with the pending patches
from [1] applied are only receiving data on RXD0 and RXD1 but not on
RXD2 and RXD3)

Emiliano, can you confirm the duplex issue observed by Simon is
similar to the one you see on your Odroid-C1?

> >>
> >>
> >> Now what happens:
> >>
> >> - benchmark between PC - ODROID is roughly 550M
> >>
> >> - benchmark between NAS - ODROID is roughly 550M
> >>
> >> - benchmark between PC - NAS is only around 300M
> >>
> >>
> >> and like i said i was easliy able to hit 800 or even 900M to my NAS
> >> earlier. I applied some .dtb fixes for interrupt levels for the
> >> meson-gx.dtsi and meson-gxbb-odroid-c2.dtb, which will be mainlined ,
> >> but the effect stayed identical.
> > good that you have the interrupt patches already applied
> > I believe it don't fix any performance issues - it's a fix for the
> > Ethernet controller seemingly getting "stuck" (not processing data
> > anymore). however, that already rules out one potential issue
> >
> >> are you aware of this problem ? Earlier kernel versions were all
> >> perfectly fine and i stepped ( self compiled) kernel through all major
> >> releases since odroid c2 was mainlined.
Guiseppe, Alexandre: what kind of data do you need from us if we see
the speeds drop (in both directions) when we send and receive at the
same time?

[...]
> the problem is that i dont have these kernel sources anymore :-(. but i
> can provide some testing and numbers. maybe i dig if i got these kernel
> configs somewhere around but i did not change much during migrating
do you remember the kernel version where it worked fine?

> im using a zyxel gs1900-8 switch and a qnap ts231p , and as i said i
> didnt change my setup. i was able to hit 100MByte/s from my NAS , so
> close to the benchmarks of 900MBit/s
I typically only do small transfers or I have traffic only in one direction.
thus it's likely that I missed this in my own tests

Regards
Martin

[0] http://lists.infradead.org/pipermail/linux-amlogic/2018-December/009679.html
[1] https://patchwork.kernel.org/cover/10744905/