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

[Y.b. Lu]

> -----Original Message-----
> From: Richard Cochran <richardcochran@xxxxxxxxx>
> Sent: 2021年4月18日 23:06
> To: Y.b. Lu <yangbo.lu@xxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx; Vladimir Oltean <vladimir.oltean@xxxxxxx>;
> David S . Miller <davem@xxxxxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>;
> Jonathan Corbet <corbet@xxxxxxx>; Kurt Kanzenbach <kurt@xxxxxxxxxxxxx>;
> Andrew Lunn <andrew@xxxxxxx>; Vivien Didelot <vivien.didelot@xxxxxxxxx>;
> Florian Fainelli <f.fainelli@xxxxxxxxx>; Claudiu Manoil
> <claudiu.manoil@xxxxxxx>; Alexandre Belloni
> <alexandre.belloni@xxxxxxxxxxx>; UNGLinuxDriver@xxxxxxxxxxxxx;
> linux-doc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> 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