Re: [Linuxptp-users] Question about meanPathDelay (possible bug?)

[Miroslav L. <mli...@re...>]

On Tue, Jul 30, 2013 at 03:06:28PM +0200, Wolfgang Wallner wrote:
> I'm not sure, but I think the "receiveTimestamp of Delay_Resp  
> message"-part is not implemented correctly in LinuxPTP.
> 
> The function process_delay_resp() calls clock_path_delay() as follows:
> 
> 	clock_path_delay(p->clock, p->delay_req->hwts.ts, m->ts.pdu,  
> m->header.correction);
> 
> The third argument is used by clock_path_delay() as what is called t4 in  
> the standard.
> As far as I understand the code, the third argument (m->ts.pdu) is the  
> ingress timestamp on the slave of the DelayResp-message.
> But I think what should be passed here should be the ingress timestamp on  
> the master of the DelayReq-message, which is contained in the  
> "receiveTimestamp"-field of the DelayResp-message (rsp->receiveTimestamp).

To me, it seems it's the DelayResp receiveTimestamp in the ts.pdu
field and used as t4 in the delay calculation. It's filled by the
following code in the msg_post_recv() function.

        case DELAY_RESP:
		timestamp_post_recv(m, &m->delay_resp.receiveTimestamp);

Why do you think it's the ingress time of the DelayResp message?

-- 
Miroslav Lichvar