[m-rev.] for post-commit review: document .par grades

[Julien Fischer]

On Mon, 18 Aug 2025 at 13:18, Peter Wang <novalazy at gmail.com> wrote:

> I'm not sure about having separate .par and .mt grade components. Is it
> more confusing that you need to use "hlc.mt.gc" but "asm_fast.par.gc" to
> get access to multi-threading, which is a practical way to exploit
> parallelism?
> On the other hand, parallel conjunction is just an
> experiment feature; there are probably no real programs using it.

I think we should just bite the bullet and use separate grade
components for concurrency
and parallel conjunction across *all* of the C grades.  Yes, it's an
extra grade component,
but it simplifies the question of how do I get a C grade that supports
concurrency?
If we disable concurrency in the (as now) non .par LLDS grades, then
having concurrency
support is matter of either using a csharp or java grade, or using a C
grade that has a ".mt"
component.

Julien.