Re: [boost] Boost.Fiber review January 6-15

12 Jan 2014

      Le 12/01/14 19:39, Oliver Kowalke a écrit :
...
2014/1/11 Vicente J. Botet Escriba 
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Le 11/01/14 19:45, Oliver Kowalke a écrit :
2014/1/11 Vicente J. Botet Escriba 
...
What would be the advantages of using work-stealing at the fiber level
...
instead of using it at the task level?
it is very simple because you migate a 'first-class' object, e.g. the
fiber
already is like a continuation.
yes, but what are the advantages? Does it performs better? It is easy to
write them?
because creating depended tasks would not block your thread-pool.
suppose you have a thread-pool of M threads and you create (without
fiber-support) many tasks N.
some of the tasks create other task, executed in the pool, and wait on the
results.
if you have enough tasks N>>M all your worker-threads of the pool would be
blocked.
something like:
void tsk() {
   ...
   for( int i = 0; i p(some_other_tsk);
     future<> f = p.get_future();
     spawn( p);
     f.get(); // blocks worker-thread
     ...
   }
   ...
}
With fibers the code above (using packaged_task<> and future<> from
boost.fiber) does not
block the worker-thread.
This is the kind of information, motivation and examples the user needs 
on the documentation ;-)

Maybe you should add how it could be done without fibers so that the 
thread doesn't blocks (you remember, we added it together on your 
thread_pool library more than 3 years ago).

Vicente