Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 19 Aug 2022 17:57:07 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     wei.fang@nxp.com
Cc:     davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] net: fec: change the default rx copybreak length to
 1518
Message-ID: <Yv+y0x6MzVmShWL9@lunn.ch>
References: <20220819090041.1541422-1-wei.fang@nxp.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220819090041.1541422-1-wei.fang@nxp.com>
Precedence: bulk

On Fri, Aug 19, 2022 at 05:00:41PM +0800, wei.fang@nxp.com wrote:
> From: Wei Fang <wei.fang@nxp.com>
> 
> Set the default rx copybreak value to 1518 so that improve the
> performance when SMMU is enabled. User can change the copybreak
> length in dynamically by ethtool.

Please provide some benchmark for this. And include a range of SoCs
which include the FEC. Maybe this helps for the platform you are
testing on, but is bad for imx25, Vybrid etc?

> + * The driver support .set_tunable() interface for ethtool, user
> + * can dynamicly change the copybreak value.
> + */

Which also means you could change it for your platform. So a patch
like this needs justifying.

     Andrew