(2017-08-16-raspbian-stretch.img / 2017-08-16-raspbian-stretch-lite.img)...
but i can't get the same accuracy as i got under Raspbian Jessie
(2017-07-05-raspbian-jessie.img / 2017-07-05-raspbian-jessie-lite.img).
under Jessie i was using NTP v4.2.8p10 compiled by myself, because the only ntp version of jessie was an old version without PPS support.
on Stretch, NTP has already version 4.2.8p10.
on Jessie the jitter of PPS against system clock was constant 0.002 after 2 hours.
on Stretch the jitter of PPS against system clock is jumping somewhere between 0.047... 0.006 after hours.
is there something installed in Raspbian Stretch, that will concurrently tune the system clock so the NTP is fighting with an other application to discipline the system clock?
Code: Select all
# /etc/ntp.conf ## Stratum1 driftfile /var/lib/ntp/ntp.drift # Enable this if you want statistics to be logged. statsdir /var/log/ntpstats/ statistics loopstats peerstats clockstats filegen loopstats file loopstats type week enable filegen peerstats file peerstats type week enable filegen clockstats file clockstats type week enable #enable stats # PPS(0), gpsd: /dev/pps0: Kernel-mode PPS ref-clock for the precise seconds # http://doc.ntp.org/current-stable/drivers/driver22.html server 127.127.22.0 minpoll 3 maxpoll 3 prefer true fudge 127.127.22.0 refid PPS time1 -0.0045 # SHM(0), gpsd: Server from shared memory provided by gpsd # # http://doc.ntp.org/current-stable/drivers/driver28.html server 127.127.28.0 minpoll 4 maxpoll 5 prefer true fudge 127.127.28.0 refid NMEA time1 0.450 stratum 10 # pool.ntp.org maps to about 1000 low-stratum NTP servers. Your server will # pick a different set every time it starts up. Please consider joining the # pool: <http://www.pool.ntp.org/join.html> #server 0.debian.pool.ntp.org iburst #server 1.debian.pool.ntp.org iburst #server 2.debian.pool.ntp.org iburst #server 3.debian.pool.ntp.org iburst # By default, exchange time with everybody, but do not allow configuration. restrict -4 default kod notrap nomodify nopeer noquery restrict -6 default kod notrap nomodify nopeer noquery # Local users may interrogate the ntp server more closely. restrict 127.0.0.1 restrict ::1