Maciek Machnikowski continues his tradition of teaching us about Time. In this session, Maciek reframes timestamps as intervals with quantified uncertainty rather than precise points, arguing that explicit uncertainty windows let applications reason about temporal correctness without hidden accuracy assumptions. He discusses sources of uncertainty such as clock sync offsets, network delay jitter, hardware timestamping limitations, and kernel-to-userspace transfer paths. Ignoring these, argues Maciek, causes errors in ordering, causality detection, and compliance checks. He will describe a time-uncertainty daemon sample and discuss Linux kernel API gaps. Come and grow your knowledge with a real human maestro! More details: https://netdevconf.info/0x1A/sessions/tutorial/making-time-uncertainty-a-fir... cheers, jamal