Time namespace

Two things (for now) we want to solve with this:

1. Shift timer's offsets
2. Make start-time remain "unchanged" after C/R
3. Continuous flow of monotonic time (CLOCK_MONOTONIC).

What about other kinds of counters like perf events and trace events?

TODO

Required in RFC

• timerfd
• timer_create()
• REALTIME offsets
• COARSE times
• RAW time
• vfs modification/creation time should work
• utime()/utimes()/futimesat() (with times == NULL)
• utimensat()/futimens() - with UTIME_NOW
• clock_nanosleep()
• mq_timedsend()/mq_timedreceive()
• semtimedop()
• btime in /proc/stat (used by pstools)
• starttime in /proc/pid/stat

Maybe later

• arm64/arm32/s390/power64 - add archs vvar support
• Adjtime (too complicated for PoC)
• Cpu time for thread/pid/pgid (times())
• /proc/stat ticks? (top uses them e.g.)
• pid creation time (probably different unrelated API)
• clock_tai - if we care about isolation from host's time

Git

• https://github.com/0x7f454c46/linux/tree/wip/time-ns

Links

• The progress of Time namespace
• Two Objects not Namespaced by the Linux Kernel
• Virtual time
• What's missing from upstream kernel containers?