GSI - HZDR

Echtzeitanwendungen und -Datenaquisition
N. Kurz GSI Darmstadt
Real Time Programming
Semaphores
time [ us 1
- system reacts deterministic on external interrupts (us)
- tasks fully preemptive (us)
- fast process synchronisation rnethods (us)
(semaphores, yield(), interrupt handling, ...)
- external interrupts must be catched 1 dispdched in
device drivers
CVC (CAMAC) MC68030 20MHz LynxOS GNU-C: 465 us
E7 (VME) MC68040 25MHz LynxOS GNU-C: 138 us
3000-500 AXP aipha ? OSFI1-HT DEC-C: 152 us
LynxOS: Real Time UNIX
TCPIIP NFS
Full development system, selfhosted
Real Time POSlX
...
yield 0;
process forces its own preemption
key function call in GSI data acqlrisition systern:
process 1 process 2
LynxOS: lnterrupt Handling
interrupts can only be catchedldispatched in
device drivers
action on interrupt in device driver itself:
1) in interrupt handler of device drlver (fast, not flexfme)
2) in system thread ( not flexlble)
interrupt dispatching into application programs:
1) Signal from interrupt handler of driver into application
program
(standard UNIX, flexible)
2) ioctl call into driver and use of system semaphore
(GSI data acquisition, fastest, flexible)
3) ...
1 hardwarcl interrupt
CVC (CAMAC) MC68030 20MHz LynxOS GNU-C: 269 us
E7 (VME) MC68040 25MHz LynxOS GNU-C: 87 us
3000-500 AXP alpha ? OSFI1-RT DEC-C: 66 us
at GSI developed: device driver for GCI CAMAC Triggermodule
GSI VME Trigprmodule