On Sat, 13 Oct 2012 23:13:31 +0300 Timur Aydin <t...@taydin.org> wrote:
> On 10/13/12 19:15, Canek Peláez Valdés wrote: > > We can only know seeing the code. Timur, this is the little test I > > made which creates 5 threads and runs them for 1 minute. In my case, > > `ps x` shows only 1 PID, care to give it a try? > > I have re-read all messages and I noticed Canek writing about the 'ps > x' output. I was using htop to watch what's happening. When I used > 'ps x', I indeed saw just a single process. Looked around google for > the difference between the two, and sure enough, htop by default > shows all threads in a process, but ps does not. You have to supply > special flags to ps to have it show the threads. > > So I started focusing on the pid's that htop is showing for my simple > app's threads. When I try to locate them under /proc/<...>, they don't > exist. Further search in google and indeed, the pid's shown for > threads aren't really "process id's" in the traditional sense and > there is no folder under /proc for them. My app has pid 12397 and one > of the threads has pid 12404. To look up the thread pid, one needs to > look under /proc/12397/task/12404. > > So, mystery (for me) solved. Thanks for all the replies! > Yes, you got it. When htop claims it's showing PIDs, it's actually lying; in fact it's showing the TIDs (thread ids), and they're different even for multiple threads within the same thread group. (For processes with just a single thread however, TID and PID are equal) Regards, aranea
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