When debugging a piece of code which rarely checks time,
uinfo wallclock can become quite imprecise. For example:
(udb) uinfo wallclock
2021-04-27T20:57:07.547331Z +/- 301288940 microseconds
...+/- 5 minutes! A section of code that doesn’t make any system calls is much rarer, so perhaps syscall handling could also fetch a timestamp (is rdtsc cheap enough and usable for interpolation?)
A use case for this is where two processes are communicating over a socket (hence making syscalls) and using wallclock to jump between corresponding sends/receives in those processes, but not needing clock times during that process.