Thanks Miroslav. The server is a Masterclock GMR1000. Funny enough, as soon as I disconnected the 1pps input pulse to that GMR1000 unit, and it falls back to GPS for reference, then the precision is improved by a lot. For example:
Stratum 1 with 1pps input (as reported in the output of chronyc ntpdata command): Remote address : ***.***.52.242 (***634F2) Remote port : 123 Local address : ***.***.52.101 (***63465) Leap status : Normal Version : 3 Mode : Server Stratum : 1 Poll interval : 10 (1024 seconds) Precision : -5 (0.031250000 seconds) Root delay : 0.000000 seconds Root dispersion : 0.000000 seconds Reference ID : 474D5200 (GMR) Reference time : Tue Apr 06 18:13:51 2021 Offset : -0.000000193 seconds Peer delay : 0.031250019 seconds Peer dispersion : 0.031250019 seconds Response time : 0.000412496 seconds Jitter asymmetry: +0.00 NTP tests : 111 111 1101 Interleaved : No Authenticated : No TX timestamping : Kernel RX timestamping : Kernel Total TX : 8095 Total RX : 8095 Total valid RX : 8095 Same stratum 1 with 1pps disconnected, shortly after, using GPS as fallback: Remote address : ***.***.52.242 (***634F2) Remote port : 123 Local address : ***.***.52.101 (***63465) Leap status : Normal Version : 3 Mode : Server Stratum : 1 Poll interval : 10 (1024 seconds) Precision : -18 (0.000003815 seconds) Root delay : 0.000000 seconds Root dispersion : 0.000000 seconds Reference ID : 474D5200 (GMR) Reference time : Tue Apr 06 18:19:15 2021 Offset : -0.000027722 seconds Peer delay : 0.000116265 seconds Peer dispersion : 0.000003832 seconds Response time : 0.000400542 seconds Jitter asymmetry: +0.00 NTP tests : 111 111 1111 Interleaved : No Authenticated : No TX timestamping : Kernel RX timestamping : Kernel Total TX : 8105 Total RX : 8105 Total valid RX : 8105 I wonder what might be causing this discrepancy between the 2 references. Thanks, Andre -- Andre Charbonneau Frequency & Time Metrology Research Centre National Research Council Canada / Government of Canada [email protected] / 613-993-3129 Fréquence et temps Centre de recherche en métrologie Conseil national de recherches Canada / Gouvernement du Canada [email protected] / 613-993-3129 -----Original Message----- From: Miroslav Lichvar [mailto:[email protected]] Sent: April 6, 2021 4:15 AM To: [email protected] Subject: Re: [chrony-users] need help with large delays reported in ntpdata ***ATTENTION*** This email originated from outside of the NRC. ***ATTENTION*** Ce courriel provient de l'extérieur du CNRC On Sat, Apr 03, 2021 at 07:33:13PM +0000, Charbonneau, André wrote: > Precision : -5 (0.031250000 seconds) > Root delay : 0.000000 seconds > Root dispersion : 0.000000 seconds > Reference ID : 474D5200 (GMR) > Reference time : Sat Apr 03 18:55:15 2021 > Offset : +0.000004316 seconds > Peer delay : 0.031250019 seconds > Peer dispersion : 0.031250019 seconds > These peer delay and peer dispersion values are quite large (being connected > to the same switch) and constant over time (they don't change). I was > looking at the chrony code and this looks like this could be due because of > large estimated error? chrony as a client rounds up the peer delay and dispersion to the precision reported by the server. -5 is not great. What kind of server is that? -- Miroslav Lichvar -- To unsubscribe email [email protected] with "unsubscribe" in the subject. For help email [email protected] with "help" in the subject. Trouble? Email [email protected]. -- To unsubscribe email [email protected] with "unsubscribe" in the subject. For help email [email protected] with "help" in the subject. Trouble? Email [email protected].
