[Gllug] Max number of pthreads in Linux ?

[Daniel P. Berrange]

On Sat, Mar 29, 2008 at 02:39:41PM +0100, salsaman at xs4all.nl wrote:
> On Sat, March 29, 2008 14:32, Progga wrote:
> > On Sat, Mar 29, 2008 at 12:44:08PM +0000, Nix wrote:
> >>
> >> Threads strike me as one of those ideas that's really great where
> >> necessary (e.g. when sharing is unavoidable, e.g. in kernel space) and
> >> otherwise really silly.
> >
> > But don't they save memory space even on Unices?
> >
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> >
> 
> I'm pretty sure they do - plus startup time is much quicker, shared memory
> is done much easier, communication is simpler, locking can be done through
> mutexes, etc.
> 
> However, in the case I was looking at for a potential client, I can so far
> see no reason to use threads as opposed to a single process. I think the
> client is under the impression that running with 10,000 threads will make
> the program run 10,000 times faster...

They're probably coming from a Solaris background where forking a process
has an order of magnitude more overhead than forking a thread. In Linux
world forking a process is already exceedingly low overhead so there is
little difference as comparing to forking a thread, unless the process
has a huge number of memory maps which need cloning.

Dan.
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