Re: Detecting threads vs processes with ps or /proc

Robert Love
2002-12-06T19:41:11Z

On Fri, 2002-12-06 at 10:24, Nick LeRoy wrote:

> >From what else I've read, it seems that the new threading model in 2.5/2.6 is
> changing to a more POSIX friendly model, which will effect this answer, but
> we're not running 2.5 and really can't force such an upgrade -- hell, right
> now we're having problems getting a switch from 2.2 pushed through.

Yep, you should get what you want with 2.5 + NPTL. We need to add a few
bits, though, to make it complete.

> Thanks _very_ much in advance. I'd be tickled pink if the answer is something
> like "just look at the foo flag in ps", or "upgrade to version 1.2.3.4 of
> procps and do xyzzy", but my intuition tells me otherwise.

See http://tech9.net/rml/procps

and "upgrade to version 2.0.8 or later of procps" :)

It is just a heuristic, though. A hack in fact. We look at a process's
children and compare RSS, VM size, and the process image they are
running. If they are the same, we label them threads.

It is the default behavior. Flag `-m' turns it off.

See thread_group() and flag_threads().

Robert Love