Are there things we should be doing to get Chrony 4.1 to take better advantage of hardware timestamps?
We've been using Chrony 3.2 with a patch to get hardware timestamps (previous thread https://listengine.tuxfamily.org/chrony.tuxfamily.org/chrony-users/2017/06/msg00017.html) and we're preparing to upgrade to 4.1, which doesn't need the patch. On our test hosts with X550 NICs, we're seeing fewer hardware timestamps under 4.1 than under 3.2. What appears to be happening is the hardware timestamps are arriving (update_tx_timestamp) after the sample has already been processed (NCR_ProcessRxKnown). We've used stap to trace the relevant calls in both versions and gather some stats. For example, two one-hour runs on the same host, one after the other: 3.2: 7956 (99.69%) timely updated timestamps averaging -85946 ns early 7 (0.09%) late updated timestamps averaging 112148 ns late 18 (0.23%) missing timestamps Timestamp types from measurements.log: D H: 25 H H: 7980 vs 4.1: 7601 (94.97%) timely updated timestamps averaging -77314 ns early 403 (5.03%) late updated timestamps averaging 118251 ns late 0 (0.00%) missing timestamps Timestamp types from measurements.log: H H: 7350 K H: 656 K K: 2 -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.