Re: Ichbiah 2022 compiler mode

On 2024-09-12 12:04, J-P. Rosen wrote:
   [...]

Well, tasks are not only for speeding up code. They can be a very useful design tool (active objects, independant activities). I think the Ada model is clean and simple, I would hate to see it disappear.

I agree.

I'm less certain about the value of priorities, [...]

Priorities are just optimization on how to manage cores when there are not enough of them.

In some contexts it could be optimization -- for example, to increase throughput in a soft real-time system -- but in hard real-time systems priorities (or deadlines) are needed for correctness, not just for optimizatiion.

I know that people use priorities to guarantee mutual exclusion, and other properties. All these algorithms were designed at the time of mono-CPU machines, but they fail on multi-cores.

In SW for multi-core systems it can be beneficial to collect tasks that frequently interact with each other or with the same single-user resources in the same core, and then the mono-core mutual-exclusion algorithms like priority ceiling inheritance can be used for that group of tasks, while using other algorithms for mutual exclusion between tasks running in different cores.