patbalbe@disca.upv.es

P. Balbastre 2002-11-06 pthread_attr_setinitbudget_np 3rtl pthread_attr_setinitbudget_np pthread_attr_getinitbudget_np examine and change the initbudget thread attribute #include <rtl_sched.h> int pthread_attr_setinitbudget_np pthread_attr_t *thread hrtime_t initbudget int pthread_attr_getinitbudget_np pthread_attr_t *thread hrtime_t *initbudget This function is a non-portable Real-Time Linux extension. pthread_attr_setinitbudget_np() and pthread_attr_getinitbudget_np() function set and get the initbudget parameter of attr structure. Before calling these functions, structure pointed by attr must be initialized by calling pthread_attr_init(). The initbudget parameter is defined for those threads whose scheduling policy is SCHED_CBS_NP. SCHED_CBS_NP scheduling policy efficiently handle soft real-time requests with a variable or unknown execution behaviour under EDF (SCHED_EDF_NP) scheduling policy. To avoid unpredictable delays on hard real-time tasks, soft tasks are isolated through a bandwidth reservation mechanism, according to wich each soft task is assigned a deadline, computed as a function of the reserved bandwidth and its actual requests. If a task requires to execute more than its expected computation time, its deadline is postponed so that its reserved bandwidth is not exceeded. SCHED_EDF_NP is a scheduling policy that combines both static and dynamic priority scheduling. Threads are ordered by priority, and among the same static priority threads with closer deadline first. Each thread has two scheduling attributes: priority and deadline. It is a Rate Monotonic policy and an EDF policy at each priority level. On initializing attr, the attribute initbudget takes the value 0. Both functions returns zero. Parameter checking is not performed. Incorrect parameters may result in random errors. Patricia Balbastre <patricia@disca.upv.es> Pau Mendoza <pabmench@disca.upv.es> pthread_setinitbudget_np(3rtl). pthread_initcbs_np(3rtl).