Hi, It might be obvious, but the offset from master is a result of the calculation of the T1-T4 timestamps. Every set of timestamps is going to give you a different number (because well, physics).
There could be several reasons for this number being larger/smaller for any set of calculations. For example, the timestamps have an error, or the packets have been delayed asymmetrically. You need to find out what it is, but the basic answer might be “buy a better clock” because there are limits to the accuracy of any implementation. What are the “media convertors” that you are talking about? Question is why is it important that every calculated offset gives you closer to zero (or well less than 100 ns)? Regards Dennis Hagarty From: Raj kishore Chhatoi <mailtoraj.b...@gmail.com> Sent: Tuesday, 22 June 2021 15:22 To: Miroslav Lichvar <mlich...@redhat.com> Cc: linuxptp-users@lists.sourceforge.net Subject: Re: [Linuxptp-users] ptp4l:Master offset in Slave is not consistently less than 100 nanosecond Hi Miroslav, I will Check the same in driver side , Meanwhile could you please suggest if there are any config changes in slave ( Servo Options ) could improve master offset in slave! # Servo Options # pi_proportional_const 0.0 pi_integral_const 0.0 pi_proportional_scale 0.0 pi_proportional_exponent -0.3 pi_proportional_norm_max 0.7 pi_integral_scale 0.0 pi_integral_exponent 0.4 pi_integral_norm_max 0.3 step_threshold 0.0 first_step_threshold 0.00002 max_frequency 900000000 clock_servo pi sanity_freq_limit 200000000 ntpshm_segment 0 msg_interval_request 0 servo_num_offset_values 10 servo_offset_threshold 0 write_phase_mode 0 # Thanks, Raj On Tue, Jun 22, 2021 at 6:22 PM Miroslav Lichvar <mlich...@redhat.com<mailto:mlich...@redhat.com>> wrote: On Tue, Jun 22, 2021 at 06:09:41PM +0530, Raj kishore Chhatoi wrote: > Hi Miroslav, > > We are not using any switch between master & slave . Masters & slaves are > connected via the Media converters. Master & slave both are connected on > the same network. I configured phc2sys (below cmd) in the slave device Ok, I guess it's an issue with the hardware or maybe driver. If you responded to the list, you might get other suggestions. -- Miroslav Lichvar -- With Regards Raj Kishore Chhatoi. Mob: +91-8608747611
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