Le mardi 6 juillet 2021 à 16:04:32 UTC+2, Albrecht Schlosser a écrit :

My basic idea is to unify (and therefore simplify) the timer event handling on all platforms. I've seen IMHO too much platform specific code to handle timer events. The more platforms we add, the more platform specific code we need to maintain.

My goal is to do as much as possible in platform independent code. This platform independent code would schedule timer events by adding them to the timer event queue - in my model the Unix/Linux code would be a valid implementation. This could be done on all current and future platforms in a platform independent way. There would also be only one platform independent timer event processing function. This could be (like) the current  Unix/Linux implementation which decrements the timer delay of all timer events in the queue.

The only platform dependent code should be the scheduling of the timer event. This could be as it is now on Unix/Linux to reduce the select/poll timer to the next timer delay or to schedule exactly one system timer on each platform which would be the delta time to the next (first) timer event. The only requirement is that the resulting timer event would call the platform independent process_timer_event() function.

For further clarification: my model would allow to use the fd approach we're using now as well as POSIX timers and Windows or macOS timers as long as we're only scheduling one timer for all systems and we're doing the timer event processing in only one system independent function. This is basically what I want to achieve.

This would allow us to get the same behavior on all current and future platforms including the optimal "repeated timer delay correction" with the minimum of platform specific code. A nice side effect would be that porting to another platform would be simplified.

Good. I think I begin to understand more clearly what is your proposal. It requires to distinguish between timer queue entries and system timers

and to have only one system timer. I had not envisaged this before. That seems to allow to much reduce the platform-specific part of timer support.

I look forward your proposal.