Re: [Linuxptp-users] Issue with initial high jitter(Path Delay Variation)

[Sujatha G. <suj...@gm...>]

Hi Miroslav Lichvar,

I tried your suggestion  by setting the pi_offset_const(set_threshold) to
0.1
but, with that the slave clock is not getting stabilized and and entering
into s2 state at all, it keeps shuffling between s0 and s1 states
It throws the error as "clock jumped backward or running slower than
expected!" some times and "clock jumped forward or running faster than
expected!" some times

Below are the the logs:
ptp4l[345.444]: selected /dev/ptp0 as PTP clock
ptp4l[345.484]: driver changed our HWTSTAMP options
ptp4l[345.489]: tx_type   1 not 1
ptp4l[345.494]: rx_filter 1 not 12
ptp4l[345.498]: port 1: INITIALIZING to LISTENING on INITIALIZE
ptp4l[345.510]: port 0: INITIALIZING to LISTENING on INITIALIZE
ptp4l[346.649]: port 1: new foreign master 001ec0.fffe.8614b5-1
ptp4l[350.649]: selected best master clock 001ec0.fffe.8614b5
ptp4l[350.654]: port 1: LISTENING to UNCALIBRATED on RS_SLAVE
ptp4l[352.826]: master offset -1553865481389947 s0 freq      +0 path delay
     5128
ptp4l[353.827]: master offset -1553865481406512 s1 freq  -16565 path delay
     5128
ptp4l[354.827]: master offset -1000000463 s0 freq  -16565 path delay
 5128
ptp4l[355.827]: master offset -999998257 s0 freq  -16565 path delay
 2769
ptp4l[356.828]: master offset -999998398 s1 freq  -16706 path delay
 2769
ptp4l[357.822]: clockcheck: clock jumped backward or running slower than
expected!
ptp4l[357.832]: master offset -481406489 s0 freq  -16706 path delay
 2769
ptp4l[358.829]: master offset -481404091 s1 freq  -14308 path delay
411
ptp4l[359.827]: master offset -1000000600 s0 freq  -14308 path delay
411
ptp4l[360.822]: clockcheck: clock jumped backward or running slower than
expected!
ptp4l[360.832]: master offset -1000003077 s0 freq  -14308 path delay
637
ptp4l[361.829]: master offset -1000005315 s1 freq  -16546 path delay
637
ptp4l[362.822]: clockcheck: clock jumped forward or running faster than
expected!
ptp4l[362.832]: master offset  518595705 s0 freq  -16546 path delay
637
ptp4l[363.829]: master offset  518595591 s1 freq  -16660 path delay
591
ptp4l[364.827]: master offset -1000005266 s0 freq  -16660 path delay
591
ptp4l[365.822]: clockcheck: clock jumped backward or running slower than
expected!
ptp4l[365.832]: master offset -1000005230 s0 freq  -16660 path delay
591
ptp4l[366.829]: master offset -1000005072 s1 freq  -16502 path delay
478
ptp4l[367.822]: clockcheck: clock jumped forward or running faster than
expected!
ptp4l[367.832]: master offset  518595452 s0 freq  -16502 path delay
478
ptp4l[368.829]: master offset  518595382 s1 freq  -16572 path delay
401
ptp4l[369.828]: master offset -1000005217 s0 freq  -16572 path delay
401
ptp4l[370.822]: clockcheck: clock jumped backward or running slower than
expected!
ptp4l[370.832]: master offset -1000005381 s0 freq  -16572 path delay
401
ptp4l[371.829]: master offset -1000005508 s1 freq  -16699 path delay
380
ptp4l[372.822]: clockcheck: clock jumped forward or running faster than
expected!
ptp4l[372.833]: master offset  518595424 s0 freq  -16699 path delay
380
ptp4l[373.829]: master offset  518595461 s1 freq  -16662 path delay
380
ptp4l[374.828]: master offset -1000005458 s0 freq  -16662 path delay
380
ptp4l[375.822]: clockcheck: clock jumped backward or running slower than
expected!
ptp4l[375.834]: master offset -1000005401 s0 freq  -16662 path delay
365
ptp4l[376.829]: master offset -1000005341 s1 freq  -16602 path delay
352



Best Regards,
Sujatha

On Mon, Feb 15, 2016 at 5:34 PM, Sujatha Guguloth <suj...@gm...>
wrote:

> Hi Miroslav Lichvar,
>
> Thank you for quick replay.
>
> We are using Linux 3.19 version and the Hardware is a proprietary FPGA
> Hardware.
>
> I will try your suggestion.
>
> Thank you.
>
> Best Regards,
> Sujatha
>
> On Mon, Feb 15, 2016 at 3:36 PM, Miroslav Lichvar <mli...@re...>
> wrote:
>
>> On Mon, Feb 15, 2016 at 02:16:13PM +0530, Sujatha Guguloth wrote:
>> > In Failire case (Logs provided below)
>> > - slave clock is taking 340 - 278 = 62 seconds for stabilization
>> > -  jitter is maintained below 100ns after stabilization but it is very
>> very
>> > high compared to previous case during the stabilization stage
>>
>> It looks like the initial step is off by one second for some reason.
>> It could be a driver issue. What HW and kernel version do you use?
>>
>> As a workaround you could try setting step_threshold to 0.1 for
>> example and allow ptp4l to correct that one second error by stepping
>> instead of slewing.
>>
>> > *Failure Logs:*
>> > ptp4l[270.981]: selected /dev/ptp0 as PTP clock
>> > ptp4l[271.014]: driver changed our HWTSTAMP options
>> > ptp4l[271.020]: tx_type   1 not 1
>> > ptp4l[271.024]: rx_filter 1 not 12
>> > ptp4l[271.028]: port 1: INITIALIZING to LISTENING on INITIALIZE
>> > ptp4l[271.040]: port 0: INITIALIZING to LISTENING on INITIALIZE
>> > ptp4l[272.323]: port 1: new foreign master 001ec0.fffe.8614b5-1
>> > ptp4l[276.323]: selected best master clock 001ec0.fffe.8614b5
>> > ptp4l[276.328]: port 1: LISTENING to UNCALIBRATED on RS_SLAVE
>> > ptp4l[278.496]: master offset -1475113437970290 s0 freq      +0 path
>> delay
>> >      7176
>> > ptp4l[279.496]: master offset -1475113437987402 s1 freq  -17112 path
>> delay
>> >      7176
>> > ptp4l[280.496]: master offset -1000000284 s2 freq -32767999 path delay
>> >  7176
>> > ptp4l[280.501]: port 1: UNCALIBRATED to SLAVE on MASTER_CLOCK_SELECTED
>> > ptp4l[281.501]: master offset -967516976 s2 freq -32767999 path delay
>>
>> --
>> Miroslav Lichvar
>>
>
>