Jan, I have a question on RTDM. Lets say I have chosen Xenomai as the FIRST platform to develop my driver with a plan to move my driver to an RTOS in future. And lets say this RTOS does not have an IO system. Does not understand any /dev/XXX entry. In that RTOS you have tasks waiting for events and you post the events from an ISR ( lets say by a message queue).
In that case, do you suggest I go for RTDM. Or I just try to mimic the same RTOS behavior by RT interrupts and rt tasks ?? -Nilanjan -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Thursday, September 14, 2006 3:11 PM To: Nilanjan Roychowdhury Cc: [email protected] Subject: Re: [Xenomai-help] driver migration Nilanjan Roychowdhury wrote: >> Performance will remain a reason to go to kernel-space, specifically if >> you either share your device between multiple processes (having a > driver >> in a separate process comes at a price...) or if you need low latency > on >> IRQ handling. But there are also reasons to go to user-space, e.g. >> license issues. We are trying to address both. > > Nilanjan :- Can I assume you are saying the latency is less when I run > my interrupt processing code as an real time ISR rather than a user - > space > Thread ? Yes, of course. Check the irqbench test for real numbers on your target system. > In that case I can run the ISR in kernel mode and signal the user space > RT task by a semaphore ( the user space task will bind this). That would be the classic design if you have some simple job to do on IRQ delivery (some direct fiddling with the hardware e.g.) + you want to wakeup a thread waiting on the event. In this case you can use RTDM for the in-kernel part and attach your application to the RTDM device your driver will then export. Jan _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
