[vardump]

I think it’s mostly due to Tracy’s poor timing calibration code. TSC is good accuracy and latency wise.

[Galanwe]

The problem is not the timestamping, it's the queue used to push profiling events which is not fast enough

[vardump]

That queue is about as fast as it gets, <10 ns. Timestamp is taken before queueing.

Again, due to bad calibration code the measured timestamps have quite a bit jitter.

Edit: TSC might not be synchronized in multi-socket systems. (Multiple physical CPU sockets). That can generate a large error.