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

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 16-06-17 12:44 , Hadrien Grasland wrote:
> So, a while ago, after playing with the nice user-mode threading
> libraries that are available these days in C++, like Intel TBB and
> HPX, I thought it would be nice if Ada had something similar.
>
> Looking around for existing work, I found a number of projects with
> custom, relatively specialized mechanisms, and a very nice library
> called Paraffin whose high-level data-parallel interface I found
> highly interesting, but whose lower-level tasking abstractions did
> not match what I had in mind.
>
> So I decided to have a go at my vision of a low-level user threading
> model, taking plenty of inspiration from other designs which I am
> fond of such as OpenCL's command queues.
>
> Today, I am confident that the resulting design and implementation is
> solid enough for third party review. So if anyone here is interested,
> please have a go at studying it on GitHub!
>
> https://github.com/HadrienG2/ada-async-tests

I had a quick first look, and it seems interesting, but I have two 
suggestions to make the development more understandable to the 
Ada-oriented reader:

- First, please do not redefine the word "task", even in the qualified 
form "asynchronous task". It is quite confusing, in the Ada context.

- Second, I question the terminology of "user thread". The "events", or 
"asynchronous tasks", are not "threads" in the sense of keeping their 
own machine-level control-flow state; they are automata that are invoked 
from the "executors" through a single "Run" operation. If some 
control-flow state must be kept between invocations of "Run", the 
"asynchronous task" must keep it in Ada-level variables/components.

I don't quite know what to call your "events" / "asynchronous tasks", 
but perhaps the term "work item", which you use in a comment, is better.

--
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
       .      @       .