Re: [boost] [Fibers] Performance

Subject: Re: [boost] [Fibers] Performance
From: Hartmut Kaiser (hartmut.kaiser_at_[hidden])
Date: 2014-01-16 12:30:43

> > > > > Now, if we were talking about hundreds of thousands of threads
> > > > > or milions of threads, it would be interesting to see numbers
> > > > > for both threads and fibers...
> > > >
> > > > FWIW, the use cases I'm seeing (and trust me those are very
> > > > commonplace at least in scientific computing) involve not just
> > > > hundreds or thousands of threads, but hundreds of millions of
> > > > threads (billions of threads a couple of years from now).
> > > >
> > > >
> > > On a single machine? That would be impressive!
> >
> > Well, it depends on the size of the machine, doesn't it? The no. 1
> > machine on the top 500 list [1] (Tianhe-2 [2]) has 3120000 cores (in
> > 16,000 compute nodes).
> >
> >
> Oh, right!
> 
> Do they usually present a single OS image to the application? I.e. do all
> the cores share a single memory address space or nodes communicate via
> message passing (MPI I presume)? std::thread-like scaling is relevant for
> the first case, less so for the later.

The conventional way how it's done is to use MPI. 
However, if you used HPX you'd see one global address space (for the things
to be sharable). 

Regards Hartmut
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