On Wed, Dec 13, 2017 at 2:28 PM, Alexander Graf <[email protected]> wrote: > > > On 13.12.17 14:00, Roger Oberholtzer wrote: >> On Wed, Dec 13, 2017 at 1:35 PM, Alexander Graf <[email protected]> wrote: >> >>> Would it make sense to resort to polling at those speeds instead? Maybe >>> poll using a constant reoccuring hrtimer? >> >> Granted polling does not have the interrupt overhead. But I wonder how >> it keeps up with respect to scheduling. Might one miss activity when >> the kernel thread is not running? > > Depends on how bad your jitter is, but I would hope that you'll get > better granularity than 23khz ;).
If jitter is too big, then perhaps if more than one interrupt is pending when already in an interrupt, only the first one is seen. I do not think interrupts are stacked. > Worst case you can always try and isolate one CPU to do nothing but > poll. You have 4 of them after all :). But that gets quite complicated ... I have also been considering that. But when we are testing, there is pretty much nothing else going on. One would expect a CPU to be ready. But if the kernel thread managing the interrupt must be set up to run, maybe that is taking time. This is getting outside my area of knowledge. I'm not sure how to do this for a kernel interrupt handler. I've only seen it for user processes. Time to Google. -- Roger Oberholtzer -- To unsubscribe, e-mail: [email protected] To contact the owner, e-mail: [email protected]
