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From:   Hayes Wang <hayeswang@realtek.com>
To:     Jakub Kicinski <kuba@kernel.org>
CC:     "davem@davemloft.net" <davem@davemloft.net>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        nic_swsd <nic_swsd@realtek.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Subject: RE: [PATCH net-next 4/6] r8152: support new chips
Thread-Topic: [PATCH net-next 4/6] r8152: support new chips
Thread-Index: AQHXMpdaTtc3dnJiRE+pHF9mj571x6q3Ka6AgAXMWPCAAEY8AIABAclQ
Date:   Wed, 21 Apr 2021 02:23:47 +0000
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Jakub Kicinski <kuba@kernel.org>
> Sent: Wednesday, April 21, 2021 2:34 AM
[...]
> > We test 2.5G Ethernet on some embedded platform.
> > And we find 64 is not large enough, and the performance
> > couldn't reach 2.5 G bits/s.
> 
> Did you manage to identify what the cause is?
> 
> NAPI will keep calling your driver if the budget was exhausted, the
> only difference between 64 and 256 should be the setup cost of the
> driver's internal loop. And perhaps more frequent GRO flush - what's
> the CONFIG_HZ set to?

I am not sure. It is more than one year ago.
The CONFIG_HZ may be 250.

First, the CPU of that platform is slower than a x86 platform.
Then, the rx data comes very fast, because of the 2.5G Ethernet.
We find the budget is always exhausted, when the traffic is busy.

Best Regards,
Hayes