-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 El 2017-12-11 a las 10:57 +0100, Roger Oberholtzer escribió:
On Mon, Dec 11, 2017 at 10:37 AM, Carlos E. R. <> wrote:
No one here interested in PREEMPT_RT and openSUSE? Is there perhaps a better list for this?
I'm curious about it but I know little.
We are exploring making a hardware controller on a Raspberry Pi 3 running openSUSE. It responds to interrupts and, based on them, manipulates some pins and, occasionally, sends off some Ethernet packets. We currently use a slower processor on an embedded card for this. It has so little memory that our app is all that can run. The network stack runs in our application. We would so like to use a real OS and off-load networking to that OS. Also, the development environment on openSUSE is so much nicer.
We would be very happy if we could get GPIO IRQs at up to 40 kHz. Our minimal kernel IRQ handler currently does nothing, and we get IRQs at up to 23 kHz. Above that we start to miss them. We are not sure if this is because of the kernel overhead, or because of the Raspberry Pi 3 hardware related to interrupts on the GPIO. I am exploring if there is anything we might be able to do to improve the Linux kernel part of the equation. We will try to keep this as a kernel driver, so we can at least eliminate the need for a context switch. At least not very often (e.g., 25 Hz).
Very interesting stuff :-) But a RT system does not guarantee speed; what it guarantees is that things are handled within a known time frame. In theory. I don't know how to calculate that time. - -- Cheers Carlos E. R. (from openSUSE 42.2 x86_64 "Malachite" (Minas Tirith)) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iF4EAREIAAYFAlouXcEACgkQja8UbcUWM1yVKQD/SXBPD9iZ4qhSoA650LIpj7pq nS81yxhzKQk431m+/ecA/2aPOHtTE9Q3NR+I4Twu2v4ocf/7Y/sQm+DQmQlfIOrX =7vBi -----END PGP SIGNATURE-----