Comment by 9d
> The downside of course is that each step of the loop is not allowed to hold the CPU for arbitrary amounts of time, and must explicitly yield for long-running tasks.
Seems to me that a bigger downside is that the more apps you have open, the slower each one will become. I don't remember ever having more than like 10 open, but I've definitely had 30 tabs open, so if they're each separate procs then wouldn't that slow each one down by 30x? I guess if the whole computer is fast enough that's fine, but intense processes like video renderers would slow down noticably, even if not fast, even if just going from 1sec to 30sec. But in any case this is a really, really clever shortcut for the general case to get a whole operating system working, which is no small feat, and really exciting!
As long as they all finish their jobs in time, they shouldn't run any slower at all. They run, they complete, they wait for the next frame. If resources are constrained enough to shrink that wait to 0 or below, then yes, everything slows down, and somewhat less gracefully than with a more fair and more complex scheduling system. But it sounds like each program yields explicitly when it's ready for the upcoming frame, so if a program doesn't have much to do, its "share" of the time is free real estate.