Yes, I know, actually it uses both processes and threads, although the main design is based on IPC between multiple processes.

As I mentioned before, that one specifically was a thread:

> So, 7728, which is a thread created by process 7727 is not listed
> under /proc/7728, but instead under /proc/7727/task/7728/

Originally Posted By Andre Goddard Rosa
hehe, checking man clone:

“The threads within a group can be distinguished by their (system-wide) unique thread IDs (TID).”

Sorry for the noise, my bad. :-P

No problem

On thing that you’ve missed is that chrome uses multiple processes, one for each web-site and not multiple threads.
If you do want to see thread IDs, check out /proc/ /task/
This is where you’ll find directory for each thread.

“The threads within a group can be distinguished by their (system-wide) unique thread IDs (TID).”

Sorry for the noise, my bad. :-P

A small nitpick:

> These numbers are system-wide

I think they are not system-wide. from linux-2.6/include/linux/sched.h:

/*
* the helpers to get the task’s different pids as they are seen
* from various namespaces
*
* task_xid_nr() : global id, i.e. the id seen from the init namespace;
* task_xid_vnr() : virtual id, i.e. the id seen from the pid namespace of
* current.

So, I think they are unique for that process, like pthread values, not system-wide.

By looking at a thread running on my system:

├─chrome(7724)─┬─chrome(7727)─┬─{chrome}(7728)

Under /proc, I have:
7723/ 7724/ 7727/

So, 7728, which is a thread created by process 7727 is not listed under /proc/7728, but instead under /proc/7727/task/7728/

p.s.: this is chrome browser, taken from here http://build.chromium.org/buildbot/snapshots/chromium-rel-linux/