Re: Raspberry Pi NTP config with fudge factors

> On May 9, 2016, at 6:39 PM, Gary E. Miller wrote: > > Yo Frank! > > On Mon, 9 May 2016 18:07:21 -0400 > Frank Nicholas wrote: > >> https://www.raspberrypi.org/forums/viewtopic.php?f=41&t=1970&start=80 >> > > I like tha

Re: Raspberry Pi NTP config with fudge factors

Yo Frank! On Mon, 9 May 2016 18:07:21 -0400 Frank Nicholas wrote: > https://www.raspberrypi.org/forums/viewtopic.php?f=41&t=1970&start=80 > I like that approach. It puts just NMEA on refclock #20 and just PPS on refclock

Re: Raspberry Pi NTP config with fudge factors

Yo Eric! On Mon, 9 May 2016 17:59:46 -0400 "Eric S. Raymond" wrote: > Frank Nicholas : > > This is the “/etc/ntp.conf” I used when I ran my NTP server on a > > Raspberry Pi with the Adafruit breakout board (same as current > > hat). I list it because of the “fudge” line. This was commonly > >

Re: Raspberry Pi NTP config with fudge factors

> On May 9, 2016, at 5:59 PM, Eric S. Raymond wrote: > > Frank Nicholas : >> This is the “/etc/ntp.conf” I used when I ran my NTP server on a Raspberry >> Pi with the Adafruit breakout board (same as current hat). I list it >> because of the “fudge” line. This was commonly accepted as the pr

Re: Raspberry Pi NTP config with fudge factors

Frank Nicholas : > This is the “/etc/ntp.conf” I used when I ran my NTP server on a Raspberry Pi > with the Adafruit breakout board (same as current hat). I list it because of > the “fudge” line. This was commonly accepted as the proper fudge settings, > especially for time2 - 0.350: How do w

Re: QNX (was: Re: Raspberry Pi NTP config with fudge factors

> On May 6, 2016, at 6:21 PM, Gary E. Miller wrote: > > The end result is both processes have the shared memory mapped into their > data space. So things get updated at raw RAM speed. Knowing it changed > needs polls, semaphores, etc. > > shmctl() is dumber, shared memory persists until reboo

Re: QNX (was: Re: Raspberry Pi NTP config with fudge factors

Yo Frank! On Fri, 6 May 2016 17:32:12 -0400 Frank Nicholas wrote: > > On May 6, 2016, at 4:19 PM, Gary E. Miller wrote: > > > > "System V shared memory (shmget(2), shmop(2), etc.) is an > > older shared memory API. POSIX shared memory provides a simpler, > > and better designed int

Re: QNX (was: Re: Raspberry Pi NTP config with fudge factors

> On May 6, 2016, at 4:19 PM, Gary E. Miller wrote: > > "System V shared memory (shmget(2), shmop(2), etc.) is an older > shared memory API. POSIX shared memory provides a simpler, and > better designed interface; on the other hand POSIX shared memory > is somewhat

Re: Raspberry Pi NTP config with fudge factors

Yo Hal! On Fri, 06 May 2016 13:15:08 -0700 Hal Murray wrote: > e...@thyrsus.com said: > > It sounds like this has implications for how I should write the > > HOWTO recipe. Are you saying that with refclock 20 the source can > > get marked as a falseticker if it loses PPS for a while? > > You

Re: QNX (was: Re: Raspberry Pi NTP config with fudge factors

Yo Eric! On Fri, 6 May 2016 15:53:15 -0400 "Eric S. Raymond" wrote: > Gary E. Miller : > > > We *will* assume POSIX-compliant shared memory on our target > > > systems. > > > > QNX has POSIX compliant shared memory, just the new one, not the > > old one. > > Are we presently using the old

Re: Raspberry Pi NTP config with fudge factors

e...@thyrsus.com said: > It sounds like this has implications for how I should write the HOWTO > recipe. Are you saying that with refclock 20 the source can get marked as a > falseticker if it loses PPS for a while? You are missing a critical idea. The NMEA and JSON drivers can be setup to use

Re: QNX (was: Re: Raspberry Pi NTP config with fudge factors

Gary E. Miller : > > We *will* assume POSIX-compliant shared memory on our target systems. > > QNX has POSIX compliant shared memory, just the new one, not the old one. Are we presently using the old one? Where is documentation for the new one? > What about Windows? It too is not our problem y

Re: QNX (was: Re: Raspberry Pi NTP config with fudge factors

Yo Eric! On Fri, 6 May 2016 15:28:40 -0400 "Eric S. Raymond" wrote: > > I'm busy today, but I'll run some tests later to verify that is the > > current behavior. At a minimum #2 makes it very hhard to see the > > NMEA time and fix a good offset. > > Please do that. On my short list. > QN

QNX (was: Re: Raspberry Pi NTP config with fudge factors

Gary E. Miller : > > It sounds like this has implications for how I should write the HOWTO > > recipe. Are you saying that with refclock 20 the source can get > > marked as a falseticker if it loses PPS for a while? > > Yup. Easy to test, just disconnect the PPS signal, if the #20 acts > like th

Re: Raspberry Pi NTP config with fudge factors

Yo Eric! On Fri, 6 May 2016 10:01:05 -0400 "Eric S. Raymond" wrote: > Gary E. Miller : > > When you disconnect the PPS, your GPS_NMEA(0) can no longer report > > PPS base time, so it will report the NMEA based time. To not so > > closely related times, mushed into one. If you GPS stop PPS when

Re: Raspberry Pi NTP config with fudge factors

Gary E. Miller : > When you disconnect the PPS, your GPS_NMEA(0) can no longer report PPS > base time, so it will report the NMEA based time. To not so closely > related times, mushed into one. If you GPS stop PPS when it does not > have a good signal the GPS_NMEA(0) will jump wildly. ntpd will

Re: Raspberry Pi NTP config with fudge factors

Yo Hal! On Thu, 05 May 2016 18:38:35 -0700 Hal Murray wrote: > > Please help me understand what's missing. > > There isn't a clean way to handle NMEA plus PPS. Is it one device or > two? It is two with refclock #28. Open and obvious. > There is a mode bit so fudge can enable/disable the P

Re: Raspberry Pi NTP config with fudge factors

> Please help me understand what's missing. There isn't a clean way to handle NMEA plus PPS. Is it one device or two? On one hand, you would like to treat them as a pair so if the NMEA says "no good", you can skip the PPS stuff. On the other hand, you would like to handle them as 2 separate d

Re: Raspberry Pi NTP config with fudge factors

Yo Frank! On Thu, 5 May 2016 20:53:32 -0400 Frank Nicholas wrote: > > On May 5, 2016, at 8:48 PM, Gary E. Miller wrote: > >> > >> I don’t know enough to answer regarding “coarse time”. Here’s my > >> output (FreeBSD-10.3-RELEASE): > > > > yeah, that's a problem with refclock #20, importa

Re: Raspberry Pi NTP config with fudge factors

> On May 5, 2016, at 8:48 PM, Gary E. Miller wrote: >> >> I don’t know enough to answer regarding “coarse time”. Here’s my >> output (FreeBSD-10.3-RELEASE): > > yeah, that's a problem with refclock #20, important data is hidden. What was missing from my ntpq -p output? I’ve included it again

Re: Raspberry Pi NTP config with fudge factors

Yo Frank! On Thu, 5 May 2016 20:23:34 -0400 Frank Nicholas wrote: > > > > Easy with the 28 refclock. Not sure on the 20. DO you even see > > the coarse time with ntpq -p? > > I don’t know enough to answer regarding “coarse time”. Here’s my > output (FreeBSD-10.3-RELEASE): yeah, that's a

Re: Raspberry Pi NTP config with fudge factors

> > Easy with the 28 refclock. Not sure on the 20. DO you even see the > coarse time with ntpq -p? I don’t know enough to answer regarding “coarse time”. Here’s my output (FreeBSD-10.3-RELEASE): [2.3-RELEASE][ad...@burns.springfield.com]/root: ntpq -p remote refid st t

Re: Raspberry Pi NTP config with fudge factors

Yo Frank! On Thu, 5 May 2016 19:41:07 -0400 Frank Nicholas wrote: > I haven’t used the NTP configuration below for years. I came up with > it from some recipe(s) I found online (some commented in the file). > The "time2 0.350" was the generally accepted best number for the > original Raspberry

Re: Raspberry Pi NTP config with fudge factors

I haven’t used the NTP configuration below for years. I came up with it from some recipe(s) I found online (some commented in the file). The "time2 0.350" was the generally accepted best number for the original Raspberry Pi A/B. I personally have no idea how to tune NTP. I just used what I t

Re: Raspberry Pi NTP config with fudge factors

Yo Frank! On Thu, 5 May 2016 18:53:42 -0400 Frank Nicholas wrote: > This is the “/etc/ntp.conf” I used when I ran my NTP server on a > Raspberry Pi with the Adafruit breakout board (same as current hat). > I list it because of the “fudge” line. This was commonly accepted as > the proper fudge s

Raspberry Pi NTP config with fudge factors

This is the “/etc/ntp.conf” I used when I ran my NTP server on a Raspberry Pi with the Adafruit breakout board (same as current hat). I list it because of the “fudge” line. This was commonly accepted as the proper fudge settings, especially for time2 - 0.350: # /etc/ntp.conf, configuration for