Hi Roger, Am 30.11.2017 um 10:59 schrieb Roger Oberholtzer:
We have written a minimal kernel interrupt handler for the Raspberry Pi 3. It is running the current 64-bit Tumbleweed kernel. I am curious about the rate of interrupts that we might be able to capture.
The ISR does little other than run when a raising edge interrupt happens. We are looking at /proc/interrupts to see how many interrupts have happened.
We see that at around 23 kHz we begin to loose interrupts. The system is not doing anything else.
Does that seem reasonable? I have not seen any good discussion of this. I think it is rather low. I am guessing that the issue is how the Linux kernel responds to interrupts. The housework in setting things up so that the interrupt can run must be the resource hog.
Opinions? Suggestions?
I don't see anything openSUSE-specific in here, so I'd suggest to ask on upstream linux-rpi-kernel list about any performance expectations. Personally I haven't had any success using GPIO interrupts on my rpi3, but that may be a matter of the device/driver (SX1276) I tried it with. Can you share any more details on DT overlay or driver init you're using to set up the interrupt? What's your interrupt source? Regards, Andreas https://github.com/afaerber/lora-modules/blob/9c5fcb64d7dac953c29da527d0f929... -- SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) -- To unsubscribe, e-mail: opensuse-arm+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-arm+owner@opensuse.org