On Sun, Jul 12, 2020 at 11:51 AM jimlux <jim...@earthlink.net> wrote:
> > Is the PPS via USB CTS stamped at interrupt time? or is it stamped > higher up in the stack? > > I started tracing this out, but then decided I'm not going to be writing > Linux USB drivers any time soon, so gave it up. > > I could easily imagine that the interrupt comes in, marks a thread as > "ready to run" and the "oh CTS has changed state" is detected at a > higher level. Best way to see this is to do live tracing. Use perf to turn on event captures with IRQs, context switches, PPS events, USB events. Then in something like Trace Compass you can see the timeline of what is actually happening. The hard IRQ context first, then maybe a context switch into a kernel thread that was made runnable by an action of the irq handler. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
