[uClinux-dev] realtime scheduling...
jwilliams at itee.uq.edu.au
Thu Mar 13 16:51:20 EST 2003
Lars Segerlund wrote:
> Basicly it runs some stuff on the NMI and the 'heavy' tasks on linux
> regular interrupts, it can hit a 15 ns window for the code to be run (
> first instruction ) on the MC5246C3 developement board, and most of it
> should be easily portable to other architectures and constraints, (
> single timer, multiple timers ). ( also I have some work left on
> verifying the behaviour of sti cli in the drivers and kernel, ie.
> estimating worst case for the linux interrupt parts ).
That's an interesting idea... Could it handle, say, interrupts from
realtime hardware other than the clock? What I'm thinking is a DSP type
system, where you have an ADC needing real-time servicing. If you could
attach it to the NMI (as well as the NMI clock), the handler reads the
data off the device, puts it in a shared memory FIFO, to be processed by
a regular uclinux process when next convenient.
Thinking about doing this on microblaze, which is a softcore (ah,
infinitely flexible hardware! :) - two separate interrupt controllers on
the INT and NMI ports of the microprocessor, and two timers. one timer
drives the NMI (real time) scheduler, the other drives the uclinux
Hardware that needs real time servicing hangs off the NMI int
controller, everything else (network controllers, UARTs etc) uses the
regular intc. Could be very interesting.
More information about the uClinux-dev