Re: RFC: Prototype for a user threading library in Ada

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 2016-07-02 13:13, Hadrien Grasland wrote:
> Le samedi 2 juillet 2016 06:36:09 UTC+2, Randy Brukardt a écrit :
>> But I don't think that really helps the race and deadlock issues that are
>> the real problem with programming with Ada tasks. I'd like to find some help
>> there, too.
>
> Here's my view of this: people are heavily overusing shared mutable
> data in multitasking programs,

This is motivated by the hardware architecture of multi-cores with 
shared memory.

> and that is the source of too many data
> races, which in turn people attempt to fix with locks, thusly killing
> their performance and introducing deadlocks.
>
> In many cases, better performance and correctness can be easily
> achieved by moving to asynchronous tasking runtimes, where the runtime
> internally manages an event-based dependency graph of tasks that can be
> processed condurrently, and data is kept task-private but can be moved
> around between tasks.

Event-controlled architecture is exposed to generators (life-locks), and 
no less to dead-locks and race conditions.

 From the software developing POV it is far worse than shared memory 
architecture. The only advantage it has over the former that it can be 
truly scalable while shared memory is a bottle neck.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de