[ntp:questions] windows device manager and serialpps.sys

Mark C. Stephens marks at non-stop.com.au
Thu Dec 1 00:27:06 UTC 2011


Upgraded to  
Version: 	Tuesday, May 11, 2010 10:22 AM       836048 ntp-4.2.7p31-win-x86-bin.zip 
Result: 	Is the GPS_NMEA broken?
Event log: 	GPS_NMEA(1) 801b 8b clock_event clk_bad_format
		GPS_NMEA(1) 801b 8b clock_event clk_no_reply
		GPS_NMEA(1) serial /dev/gps1 open at 9600 bps

Was working before so apply the n-1 theory:
Version: 	Saturday, October 15, 2011  3:32 AM       932341 ntp-4.2.7p224-win-x86-bin.zip
Result:	Bingo! (I think)
C:\Program Files\NTP\bin>ntpd -n -M -g -c "C:\Program Files\NTP\etc\ntp.conf"
 1 Dec 10:24:50 ntpd[6028]: ntpd 4.2.7p224-o Oct 14 19:58:02.91 (UTC-00:00) 2011  (1)
 1 Dec 10:24:50 ntpd[6028]: Raised to realtime priority class
 1 Dec 10:24:50 ntpd[6028]: MM timer resolution: 1..1000000 msec, set to 1 msec
 1 Dec 10:24:50 ntpd[6028]: Performance counter frequency 1263.420 MHz
 1 Dec 10:24:50 ntpd[6028]: Clock interrupt period 15.625 msec (startup slew 0.1 usec/period)
 1 Dec 10:24:50 ntpd[6028]: Windows clock precision 15.625 msec, min. slew 6.400 ppm/s
 1 Dec 10:24:50 ntpd[6028]: HZ 64.000 using 43 msec timer 23.256 Hz 64 deep
 1 Dec 10:24:53 ntpd[6028]: proto: precision = 0.800 usec
 1 Dec 10:24:53 ntpd[6028]: Listen and drop on 0 v4wildcard 0.0.0.0:123
 1 Dec 10:24:53 ntpd[6028]: Listen normally on 1 NIC1 192.168.5.8:123
 1 Dec 10:24:53 ntpd[6028]: Listen normally on 2 MS TCP Loopback interface 127.0.0.1:123
 1 Dec 10:24:53 ntpd[6028]: peers refreshed
 1 Dec 10:24:53 ntpd[6028]: GPS_NMEA(1) serial /dev/gps1 open at 9600 bps
time_pps_create(4) got winhandle 00000620
getenv(PPSAPI_DLLS) gives c:\serialpps\serialpps-ppsapi-provider\x86\serialpps-ppsapi-provider.dll
loaded PPSAPI provider serialpps.sys, serial.sys with CD timestamping added caps 0x3011 provider 00B6F5B0
serialpps prov_time_pps_create(00000620) returned 0
 1 Dec 10:24:53 ntpd[6028]: 0.0.0.0 c012 02 freq_set ntpd 5.798 PPM
 1 Dec 10:24:53 ntpd[6028]: 0.0.0.0 c016 06 restart
  1 Dec 10:24:54 ntpd[6028]: 0.0.0.0 c415 05 clock_sync
 1 Dec 10:37:27 ntpd[6028]: ctr 1263.412 MHz  -6.46 PPM using 1263.417 MHz  -2.15 PPM


Within the hour:
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*GPS_NMEA(1)     .GPS.            0 l    7   16  377    0.000    0.013   0.052

Best performance I have seen.

As with all things NTPD I will report back in a day or so..


Mark




-----Original Message-----
From: Dave Hart [mailto:davehart at gmail.com] 
Sent: Thursday, 1 December 2011 1:51 AM
To: Mark C. Stephens
Cc: questions at lists.ntp.org
Subject: Re: [ntp:questions] windows device manager and serialpps.sys

On Tue, Nov 29, 2011 at 14:54, Mark C. Stephens <marks at non-stop.com.au> wrote:
> I am running 4.2.7p98-o and I am uncertain whether or not PPS is working.

That's a relatively antique snapshot of ntp-dev.  At least with more recent ntp-dev, if PPSAPI is enabled for NMEA using flag1 1 as you have, the NMEA refclock driver will log an error message on startup if PPSAPI is not working that mentions both PPSAPI and flag1 1.  See your event log or a configured ntp.log.

There are less direct things you could try, like see if manually lowering the ntpd process priority class from Realtime to Low then throwing some work at the machine increases the offset ntpd reports for the NMEA association.  If PPSAPI is working the timestamps are snapped at serial port interrupt time and will not be affected by additional ntpd scheduling latency.

Cheers,
Dave Hart




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