On Thu, 6 Feb 2025 15:27:17 +0100 Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > I'm assuming you have a recent number around -- what's sane? 5us, less? It really doesn't matter what the number is. No matter what it is, it adds to the latency. Just adding the timer and another interrupt just doubled the interrupt latency. If an RT task were to wake up but this flag is set to extend the currently running task, even if you made it 5us, it will be more than that. You need to enable a new timer, get back to user space, trigger another interrupt, before you can schedule the RT task from its original time it was to wake up and run. -- Steve
