When triggered by pressing the VSTATUS key or calling the TIOCSTAT
ioctl, the n_tty line discipline will display a message on the user's
tty that provides basic information about the system and an
'interesting' process in the current foreground process group, eg:
load: 0.58 cmd: sleep 744474 [sleeping] 0.36r 0.00u 0.00s 0% 772k
The status message provides:
- System load average
- Command name and process id (from the perspective of the session)
- Scheduler state
- Total wall-clock run time
- User space run time
- System space run time
- Percentage of on-cpu time
- Resident set size
The message is only displayed when the tty has the VSTATUS character
set, the local flags ICANON and IEXTEN are enabled and NOKERNINFO is
disabled; it is always displayed when TIOCSTAT is called regardless of
tty settings.
Signed-off-by: Walt Drummond <walt@xxxxxxxxxxx>
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