[RFC v3 3/3] examples/ptpclient: add frequency adjustment support

[Su, Simei]

Hi Ferruh,

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit at amd.com>
> Sent: Saturday, June 3, 2023 3:53 AM
> To: Su, Simei <simei.su at intel.com>; thomas at monjalon.net;
> andrew.rybchenko at oktetlabs.ru; Rybalchenko, Kirill
> <kirill.rybalchenko at intel.com>; Zhang, Qi Z <qi.z.zhang at intel.com>
> Cc: dev at dpdk.org; Wu, Wenjun1 <wenjun1.wu at intel.com>
> Subject: Re: [RFC v3 3/3] examples/ptpclient: add frequency adjustment
> support
> 
> On 5/22/2023 2:23 PM, Simei Su wrote:
> > This patch applys PI servo algorithm to leverage frequency adjustment
> > API to improve PTP timesync accuracy.
> >
> > The command for starting ptpclient with PI algorithm is:
> > ./build/examples/dpdk-ptpclient -a 0000:81:00.0 -c 1 -n 3 -- -T 0 -p
> > 0x1 --controller=pi
> >
> > Signed-off-by: Simei Su <simei.su at intel.com>
> > Signed-off-by: Wenjun Wu <wenjun1.wu at intel.com>
> > ---
> >  examples/ptpclient/ptpclient.c | 178
> > +++++++++++++++++++++++++++++++++++++----
> >  1 file changed, 161 insertions(+), 17 deletions(-)
> >
> 
> <...>
> 
> > +
> > +enum controller_mode {
> > +	MODE_NONE,
> > +	MODE_PI,
> > +	MAX_ALL
> > +} mode;
> > +
> 
> Better to have 'mode' variable as 'static', can be good to split enum and
> variable declaration.
> 

OK, got it. Thanks for your reminder.

> <...>
> 
> > @@ -608,11 +729,14 @@ parse_ptp_frames(uint16_t portid, struct
> rte_mbuf *m) {
> >  			break;
> >  		case FOLLOW_UP:
> >  			parse_fup(&ptp_data);
> > +			if (mode == MODE_PI)
> > +				ptp_adjust_freq(&ptp_data);
> >  			send_delay_request(&ptp_data);
> >  			break;
> >  		case DELAY_RESP:
> >  			parse_drsp(&ptp_data);
> > -			ptp_adjust_time(&ptp_data);
> > +			if (mode == MODE_NONE)
> > +				ptp_adjust_time(&ptp_data);
> >  			print_clock_info(&ptp_data);
> >  			break;
> >  		default:
> >
> 
> Why with FOLLOW_UP PTP message only frequency adjustment done, and
> with DELAY_RESP PTP message only time adjustment done?
> 
> Is this related to he PTP protocol, or your design decision?

It's my design. In current design, if it's without PI algorithm, it only involves time adjustment for "DELAY_RESP PTP message" which is original framework.
If it's with PI algorithm, it involves time adjustment or frequency adjustment based on output state in PI algorithm for " FOLLOW_UP PTP message" while
for " DELAY_RESP PTP message", it only needs to print clock info.

Thanks,
Simei