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Date:   Wed, 03 Apr 2019 18:35:21 +0300
From:   "Leonidas P. Papadakos" <papadakospan@gmail.com>
Subject: RE: [PATCH 1/2] stmmac: introduce flag to dynamically disable TX
 offload for rockchip devices
To:     Jose Abreu <jose.abreu@synopsys.com>
Cc:     Robin Murphy <robin.murphy@arm.com>,
        Philipp Tomsich <philipp.tomsich@theobroma-systems.com>,
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        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        netdev@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Klaus Goger <klaus.goger@theobroma-systems.com>
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=CE=A3=CF=84=CE=B9=CF=82 =CE=A4=CE=B5=CF=84, 3 =CE=91=CF=80=CF=81, 2019 at =
10:55 =CE=A0=CE=9C, =CE=BF/=CE=B7 Jose Abreu=20
<jose.abreu@synopsys.com> =CE=AD=CE=B3=CF=81=CE=B1=CF=88=CE=B5:
> From: Leonidas P. Papadakos <papadakospan@gmail.com>
> Date: Tue, Apr 02, 2019 at 23:48:16
>=20
>>  I can confirm that snps,no-pbl-x8, currently set by uboot for the=20
>> fdt
>>  basically fixes the tx-checksumming issue.
>>  I get 700~800 Mbps myself but that might come down to the setup.
>>  You could say it affects performance slightly, as I saw in a=20
>> previous
>>  email.
>>=20
>>  Without the setting The rate consistently drops to 0.
>>  ethtool reports tx-checksumming is on in both cases
>>=20
>>  Pretty cool!
>>  Does that give you guys an idea on how to tackle it "officially"?
>>=20
>>=20
>>=20
>=20
> Thank you all for testing !
>=20
> It's been on my todo list to cook up a patch that limits PBL=20
> according to
> FIFO size but I didn't manage to have the time yet so for now it would
> be better if you fix it by submitting the DT bindings changes.
>=20
> Thanks,
> Jose Miguel Abreu

If snps,no-pbl-x8 does indeed have a performace hit, should the=20
workaround be to
a) turn tx checksumming off or
b) snps,no-pbl-x8 set?

I'll test to see the difference

=