RE: [net-next 1/3] net: dsa: optimize tx timestamp request handling

["Y.b. Lu" <yangbo.lu@nxp.com>]

> -----Original Message-----
> From: Richard Cochran <richardcochran@gmail.com>
> Sent: 2021年4月18日 23:06
> To: Y.b. Lu <yangbo.lu@nxp.com>
> Cc: netdev@vger.kernel.org; Vladimir Oltean <vladimir.oltean@nxp.com>;
> David S . Miller <davem@davemloft.net>; Jakub Kicinski <kuba@kernel.org>;
> Jonathan Corbet <corbet@lwn.net>; Kurt Kanzenbach <kurt@linutronix.de>;
> Andrew Lunn <andrew@lunn.ch>; Vivien Didelot <vivien.didelot@gmail.com>;
> Florian Fainelli <f.fainelli@gmail.com>; Claudiu Manoil
> <claudiu.manoil@nxp.com>; Alexandre Belloni
> <alexandre.belloni@bootlin.com>; UNGLinuxDriver@microchip.com;
> linux-doc@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [net-next 1/3] net: dsa: optimize tx timestamp request handling
> 
> On Fri, Apr 16, 2021 at 08:36:53PM +0800, Yangbo Lu wrote:
> > Optimization could be done on dsa_skb_tx_timestamp(), and dsa device
> > drivers should adapt to it.
> >
> > - Check SKBTX_HW_TSTAMP request flag at the very beginning, instead of in
> >   port_txtstamp, so that most skbs not requiring tx timestamp just return.
> >
> > - No longer to identify PTP packets, and limit tx timestamping only for PTP
> >   packets. If device driver likes, let device driver do.
> >
> > - It is a waste to clone skb directly in dsa_skb_tx_timestamp().
> >   For one-step timestamping, a clone is not needed. For any failure of
> >   port_txtstamp (this may usually happen), the skb clone has to be freed.
> >   So put skb cloning into port_txtstamp where it really needs.
> 
> This patch changes three things ^^^ at once.  These are AFAICT independent
> changes, and so please break this one patch into three for easier review.

Will split it in next version. Thank you.

> 
> Thanks,
> Richard