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Include dependency graph for sched_up.c:
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int | rt_task_init (RT_TASK *task, void(*rt_thread)(int), int data, int stack_size, int priority, int uses_fpu, void(*signal)(void)) |
int | rt_task_init_cpuid (RT_TASK *task, void(*rt_thread)(int), int data, int stack_size, int priority, int uses_fpu, void(*signal)(void), unsigned int cpuid) |
void | rt_set_runnable_on_cpus (RT_TASK *task, unsigned long runnable_on_cpus) |
Assign CPUs to a task. | |
void | rt_set_runnable_on_cpuid (RT_TASK *task, unsigned int cpuid) |
Assign CPUs to a task. | |
void | rt_sched_lock (void) |
Lock the scheduling of tasks. | |
void | rt_sched_unlock (void) |
Unlock the scheduling of tasks. | |
int | rt_task_delete (RT_TASK *task) |
void | rt_set_periodic_mode (void) |
Set timer mode. | |
void | rt_set_oneshot_mode (void) |
Set timer mode. | |
RTIME | start_rt_timer (int period) |
Start timer. | |
void | start_rt_apic_timers (struct apic_timer_setup_data *setup_mode, unsigned int rcvr_jiffies_cpuid) |
Start local apic timer. | |
void | stop_rt_timer (void) |
Stop timer. | |
void | rt_preempt_always (int yes_no) |
Enable hard preemption. | |
void | rt_preempt_always_cpuid (int yes_no, unsigned int cpuid) |
Enable hard preemption. | |
RTIME | count2nano (RTIME counts) |
Convert internal count units to nanoseconds. | |
RTIME | nano2count (RTIME ns) |
Convert nanoseconds to internal count units. | |
RTIME | count2nano_cpuid (RTIME counts, unsigned int cpuid) |
Convert internal count units to nanoseconds. | |
RTIME | nano2count_cpuid (RTIME ns, unsigned int cpuid) |
Convert nanoseconds to internal count units. | |
RTIME | rt_get_time (void) |
Get the current time. | |
RTIME | rt_get_time_cpuid (unsigned int cpuid) |
Get the current time. | |
RTIME | rt_get_time_ns (void) |
Get the current time. | |
RTIME | rt_get_time_ns_cpuid (unsigned int cpuid) |
Get the current time. | |
RTIME | rt_get_cpu_time_ns (void) |
Get the current time. |
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Convert internal count units to nanoseconds. This function converts the time of timercounts internal count units into nanoseconds. Remember that the count units are related to the time base being used (see functions rt_set_oneshot_mode() and rt_set_periodic_mode() for an explanation).
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Convert internal count units to nanoseconds. This function converts the time of timercounts internal count units into nanoseconds. It is to be used with the MUP scheduler since with such a scheduler it is possible to have independent timers, i.e. periodic of different periods or a mixing of periodic and oneshot, so that it is impossible to establish which conversion units should be used in the case one asks for a conversion from any CPU for any other CPU. All these functions have the same behavior with UP and SMP schedulers.
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Convert nanoseconds to internal count units. This function converts the time of nanosecs nanoseconds into internal counts units. Remember that the count units are related to the time base being used (see functions rt_set_oneshot_mode() and rt_set_periodic_mode() for an explanation). The versions ending with_cpuid are to be used with the MUP scheduler since with such a scheduler it is possible to have independent timers, i.e. periodic of different periods or a mixing of periodic and oneshot, so that it is impossible to establish which conversion units should be used in the case one asks for a conversion from any CPU for any other CPU. All these functions have the same behavior with UP and SMP schedulers.
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Convert nanoseconds to internal count units. This function converts the time of nanosecs nanoseconds into internal counts units. Remember that the count units are related to the time base being used (see functions rt_set_oneshot_mode() and rt_set_periodic_mode() for an explanation). This function is to be used with the MUP scheduler since with such a scheduler it is possible to have independent timers, i.e. periodic of different periods or a mixing of periodic and oneshot, so that it is impossible to establish which conversion units should be used in the case one asks for a conversion from any CPU for any other CPU. All these functions have the same behavior with UP and SMP schedulers.
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Get the current time. rt_get_cpu_time_ns always returns the CPU time in nanoseconds whatever timer is in use.
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Get the current time. rt_get_time returns the time, in internal count units, since start_rt_timer was called. In periodic mode this number is in multiples of the periodic tick. In oneshot mode it is directly the TSC count for CPUs having a time stamp clock (TSC), while it is a (FIXME) on 8254 units for those not having it (see functions rt_set_oneshot_mode() and rt_set_periodic_mode() for an explanation).
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Get the current time. rt_get_time_cpuid returns the time, in internal count units, since start_rt_timer was called. In periodic mode this number is in multiples of the periodic tick. In oneshot mode it is directly the TSC count for CPUs having a time stamp clock (TSC), while it is a (FIXME) on 8254 units for those not having it (see functions rt_set_oneshot_mode() and rt_set_periodic_mode() for an explanation). This version ending with _cpuid must be used with the MUP scheduler when there is the need to declare from which cpuid the time must be gotten (FIXME). In fact one can need to get the time of another CPU and timers can differ from CPU to CPU. (FIXME) All these functions have the same behavior with UP and SMP schedulers.
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Get the current time. rt_get_time_ns is the same as rt_get_time() but the returned time is converted to nanoseconds.
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Get the current time. rt_get_time_ns is the same as rt_get_time but the returned time is converted to nanoseconds. The version ending with _cpuid must be used with the MUP scheduler when there is the need to declare from which cpuidthe time must be got. In fact one can need to get the time of another CPU and timers can differ from CPU to CPU. All these functions have the same behavior with UP and SMP schedulers.
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Enable hard preemption. In the oneshot mode the next timer expiration is programmed after a timer shot by choosing among the timed tasks the one with a priority higher than the task chosen to run as current, with the constraint of always assuring a correct Linux timing. In such a view there is no need to fire the timer immediately. In fact it can happen that the current task can be so fast to get suspended and rerun before the one that was devised to time the next shot when it was made running. In such a view RTAI schedulers try to shoot only when strictly needed. This minimizes the number of slow setups of the 8254 timer used with UP and 8254 based SMP schedulers. While such a policy minimizes the number of actual shots, greatly enhancing efficiency, it can be unsuitable when an application has to be guarded against undesired program loops or other unpredicted error causes. Calling these functions with a nonzero value assures that a timed high priority preempting task is always programmed to be fired while another task is currently running. The default is no immediate preemption in oneshot mode, i.e. firing of the next shot programmed only when strictly needed to satisfy tasks timings.
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Enable hard preemption. In the oneshot mode the next timer expiration is programmed after a timer shot by choosing among the timed tasks the one with a priority higher than the task chosen to run as current, with the constraint of always assuring a correct Linux timing. In such a view there is no need to fire the timer immediately. In fact it can happen that the current task can be so fast to get suspended and rerun before the one that was devised to time the next shot when it was made running. In such a view RTAI schedulers try to shoot only when strictly needed. This minimizes the number of slow setups of the 8254 timer used with UP and 8254 based SMP schedulers. While such a policy minimizes the number of actual shots, greatly enhancing efficiency, it can be unsuitable when an application has to be guarded against undesired program loops or other unpredicted error causes. Calling these functions with a nonzero value assures that a timed high priority preempting task is always programmed to be fired while another task is currently running. The default is no immediate preemption in oneshot mode, i.e. firing of the next shot programmed only when strictly needed to satisfy tasks timings.
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Lock the scheduling of tasks. rt_sched_lock, lock on the CPU on which they are called, any scheduler activity, thus preventing a higher priority task to preempt a lower priority one. They can be nested, provided unlocks are paired to locks in reversed order. It can be used for synchronization access to data among tasks. Note however that under MP the lock is active only for the CPU on which it has been issued, so it cannot be used to avoid races with tasks that can run on any other available CPU. Interrupts are not affected by such calls. Any task that needs rescheduling while a scheduler lock is in placewill be only at the issuing of the last unlock
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Unlock the scheduling of tasks. rt_sched_unlock, unlock on the CPU on which they are called, any scheduler activity, thus preventing a higher priority task to preempt a lower priority one. They can be nested, provided unlocks are paired to locks in reversed order. It can be used for synchronization access to data among tasks. Note however that under MP the lock is active only for the CPU on which it has been issued, so it cannot be used to avoid races with tasks that can run on any other available CPU. Interrupts are not affected by such calls. Any task that needs rescheduling while a scheduler lock is in placewill be only at the issuing of the last unlock
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Set timer mode. rt_set_periodic_mode sets the periodic mode for the timer. It consists of a fixed frequency timing of the tasks in multiple of the period set with a call to start_rt_timer(). The resolution is that of the 8254 (1193180 Hz) on a UP machine, or if the 8254 based SMP scheduler is being used. For the SMP scheduler timed by the local APIC timer and for the MUP scheduler the timer resolution is that of the local APIC timer frequency, generally the bus frequency divided 16. Any timing request not being an integer multiple of the set timer period is satisfied at the closest period tick. It is the default mode when no call is made to set the oneshot mode.
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Set timer mode. rt_set_periodic_mode sets the periodic mode for the timer. It consists of a fixed frequency timing of the tasks in multiple of the period set with a call to start_rt_timer(). The resolution is that of the 8254 (1193180 Hz) on a UP machine, or if the 8254 based SMP scheduler is being used. For the SMP scheduler timed by the local APIC timer and for the MUP scheduler the timer resolution is that of the local APIC timer frequency, generally the bus frequency divided 16. Any timing request not being an integer multiple of the set timer period is satisfied at the closest period tick. It is the default mode when no call is made to set the oneshot mode.
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Assign CPUs to a task. rt_set_runnable_on_cpuid select one or more CPUs which are allowed to run task task. rt_set_runnable_on_cpuid assigns a task to a single specific CPU. If no CPU, as selected by cpu_mask or cpuid, is available, both functions choose a possible CPU automatically, following the same rule as above.
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Assign CPUs to a task. rt_set_runnable_on_cpus selects one or more CPUs which are allowed to run task task. rt_set_runnable_on_cpus behaves differently for MUP and SMP schedulers. Under the SMP scheduler bit<n> of cpu_mask enables the task to run on CPU<n>. Under the MUP scheduler it selects the CPU with less running tasks among those allowed by cpu_mask. Recall that with MUP a task must be bounded to run on a single CPU. If no CPU, as selected by cpu_mask or cpuid, is available, both functions choose a possible CPU automatically, following the same rule as above.
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rt_task_delete deletes a real time task previously created by rt_task_init() or rt_task_init_cpuid().
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The newly created real time task is initially in a suspend state. It can be made active by calling: rt_task_make_periodic, rt_task_make_periodic_relative_ns, rt_task_resume. When used with the MUP scheduler rt_task_init automatically selects which CPU the task will run on, while with the SMP scheduler the task defaults to using any of the available CPUs. This assignment may be changed by calling rt_set_runnable_on_cpus.
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Creates a new real time task and assigns it to a single specific CPU. The newly created real time task is initially in a suspend state. It can be made active by calling: rt_task_make_periodic, rt_task_make_periodic_relative_ns, rt_task_resume. When used with the MUP scheduler rt_task_init automatically selects which CPU the task will run on, while with the SMP scheduler the task defaults to using any of the available CPUs. This assignment may be changed by calling rt_set_runnable_on_cpus or rt_set_runnable_on_cpuid. If cpuid is invalid rt_task_init_cpuid falls back to automatic CPU selection. Whatever scheduler is used on multiprocessor systems rt_task_init_cpuid allows to create a task and assign it to a single specific CPU cpuid from its very beginning, without any need to call rt_set_runnable_on_cpuid later on.
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Start local apic timer. start_rt_apic_timers starts local APIC timers according to what is found in setup_data.
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Start timer. start_rt_timer starts the timer with a period period. The period is in internal count units and is required only for the periodic mode. In the oneshot mode the period value is ignored. This functions uses the 8254 with the UP and the 8254 based SMP scheduler. Otherwise it uses a single local APIC with the APIC based SMP schedulers and an APIC for each CPU with the MUP scheduler. In the latter case all local APIC timers are paced in the same way, according to the timer mode set.
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Stop timer. stop_rt_timer stops the timer. The timer mode is set to periodic.
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