Bafflingly baroque Debian ps: show threads in forest tree

Question

My favourite ps invocation is:

ps -efww ef

as I need to watch all processes (-e), get extended information about them (-f), see the environment (e) they operate within, wrapping lines (-w -w) so I don't lose any part of that, and visually group (f) child processes under their parents, for an at-a-glance overview.

I have "wasted" the whole morning trying to get any thread information to appear as well, following the same visualisation logic above. I must have tried 40 different combinations of options. (Actually, I just checked my .bash_history and I have tried more!). Combinations included swapping f and -H for forest display, for instance. Sometimes I even tried permutations to check insidious "orderings"...

None of the threading options seem to be compatible with my "monitoring screen" setup. I am talking about H, -L, m, -m and -T.

I am baffled. Am I doing it wrong? How are you guys doing it?

Specifically: I need to watch for processes like download managers who go funky with 30 to 80 threads all of a sudden...

Answer 1

To watch for processes that create a lot of threads, I think all that's relevant is the number of threads per process, so go with

ps -o pid -o thcount

plus any option to select which processes to match, such as -e or -C. Run the command periodically and watch for sudden changes in thcount. This will give you approximate results (for example, you won't detect if a PID is reused between calls) but that should be good enough for your purpose.

Note that you can limit the number of threads per process:

(ulimit -T 20; downloadmanager)