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Download Comparative Study on Real Time Enhanced Linux
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46 CHAPTER 2. KERNEL SPACE API executing on pthread_wait_np - suspend the execution of the calling thread until the next period (for periodic tasks). pthread_delete_np - delete the thread in a rt-asfe way from non-rt context (providing a timeout mechanism). pthread_attr_setfp_np - mark the created thread as using or not using the FPU pthread_setfp_np - mark the thread as using or not using the FPU pthread_make_periodic_np - set timing parameters for periodic threads execution pthread_suspend_np - suspend the execution of the calling thread. pthread_wakeup_np - wake up the thread To build periodic threads without utilizing POSIX timers and signals the np extensions to the API can be used , currently these are somewhat more effective due to the implementation details than the ‘pure POSIX‘ solutions for periodic task execution, this should though only be relevant for low-end systems (X86 below 133MHz). Never the less we recomend using the POSIX style API for portability and consistancy of semantics, even at the price of some performance loss. 2.3.7 Backwars/Forwards Compatibility Note that ‘pure-POSIX‘ is posible in RTLinux/GPL and the API development is focused towards improving POSIX compatibility and completness. RTLinux has provided backwards compatibility in the past all the way back to the V1 API (non-POSIX) but this compatibility is at the price of reduced performance. This reduction of performance is due to the backwards compatibility being provided via wrappers to the V3 API - so backwards compatibility is not using the original implementation. To utilize the full performance and stay compatible to future releases of RTLinux/GPL pure-POSIX is advocated. We recomend not using the V1 API unless actually running on V1.X RTLinux systems. For projects utilizing the current API, POSIX should be the guiding coding standard. 2.4 RTLinux/Pro The RTLinux/Pro API for the first release (Dev-Kit 1.0) is identical to the RTLinux/GPL V3.1 API, at which time the splitt between RTLinux/GPL and RTLinux/Pro occured.
