Re: pthread_barrier type and functions

[Mohammad Akhlaghi]

Hi Bruno,

Thanks for introducing the two cases, it is very interesting. I 
understand the first option (glibc's implementation) better, but if the 
second is a more fundamental approach maybe that should be used. As long 
as all the pthread_barrier functions become available.

I am an astronomy PhD student and have not officially had any computer 
science courses (although I am very interested to learn, as I have until 
now). I will definitely read the "Little book on Semaphores" to 
understand them better.

Thank you for the links,
Mohammad

On 03/08/2015 08:51 PM, Bruno Haible wrote:
> Mohammad Akhlaghi wrote:
> > I have made extensive use of the pthread_barrier_* types and functions
> > for the parallel processing parts of gnuastro. But I found out Gnulib
> > doesn't include them. I wanted to see if it would be possible for you to
> > include these in the Gnulib version of pthread. Using a pthread_barrier
> > is simpler than using a mutex and condition variable together when the
> > jobs are completely independent.
> Which one of these two implementation approaches would be better:
>
> a) using the same design as glibc,
>     
> https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/DESIGN-barrier.txt;hb=HEAD
>     possibly with an additional lock for the atomic increment?
>
> b) using two semaphores, as in
>     
> http://stackoverflow.com/questions/6331301/implementing-an-n-process-barrier-using-semaphores
>     (possibly replacing the second semaphore with a pthread_cond_t ?)
>
> [I'm not going to implement it. Just trying to give food for thought.]
>
> Bruno