Useful idea. I sometimes use time [1] to print stats at the end of the program's run, like so.
/usr/bin/time -f 'user=%U system=%S maxrss=%M ins=%I outs=%O" PROGRAM
Seeing stats while the program is running is nice though! Also, cumulative monitoring of an entire foreground process group would be super handy (a long build, for instance).
Drop the --target-output option, you don't need it. Same thing can be achieved with:
monner.py sh -c 'exec 1>/dev/null 2>&1 $0 "$@"' PROGRAM
I also agree with the other commenter that monner should be the parent process.
[1] Note, time(1) is not the same as the shell builtin of the same name.
what does "memory" mean here? it would be nice to have more details (eg virtual v physical). also disk io (with paging separate) would be good. and maybe files opened (like /prod/PID/fd/*)
it would be really nice to have something that shows all this for a single process (and perhaps also for other processes that are "top" in some category). at the moment, when i am trying to balance code to run as well as possible within given hardware constraints, i have to juggle various monitor programs - this is a good first step to using just one...
The monitor is stopped as soon as the target process finishes - which means that the very last reading emitted will only contain information from during the run of the target.
If it were done the other way around then we'd have to poll for the termination of the forked target process. Either the poll duration would have to be really small or the monitor would contain readings for some time after the end of the target.
This isn't so bad when running with an interval of 1 second... but for an interval of 1 minute (or longer) it can start to give odd readings.
To be honest, I'm thinking of removing the very final reading anyway. Or, at least documenting that the final reading may be slightly misleading.
Ah. I was mucking around in the subprocess module at one point, and IIRC it already forks the subprocess that it launches, even if you're just doing something like subprocess.call().
Drop the --target-output option, you don't need it. Same thing can be achieved with:
I also agree with the other commenter that monner should be the parent process.[1] Note, time(1) is not the same as the shell builtin of the same name.