sched.h File Reference

Scheduler API definition. More...

Detailed Description

Scheduler API definition.

Author
Kaspar Schleiser kaspa.nosp@m.r@sc.nosp@m.hleis.nosp@m.er.d.nosp@m.e

Definition in file sched.h.

#include <stddef.h>
#include <inttypes.h>
#include "kernel_defines.h"
#include "native_sched.h"
#include "clist.h"
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Macros

#define MAXTHREADS   32
 The maximum number of threads to be scheduled.
 
#define KERNEL_PID_UNDEF   0
 Canonical identifier for an invalid PID.
 
#define KERNEL_PID_FIRST   (KERNEL_PID_UNDEF + 1)
 The first valid PID (inclusive).
 
#define KERNEL_PID_LAST   (KERNEL_PID_FIRST + MAXTHREADS - 1)
 The last valid PID (inclusive).
 
#define PRIkernel_pid   PRIi16
 Macro for printing formatter.
 
#define SCHED_TEST_STACK   1
 Enables detection of stack overflows and measures stack usage when != 0.
 
#define SCHED_PRIO_LEVELS   16
 The number of thread priority levels.
 

Typedefs

typedef int16_t kernel_pid_t
 Unique process identifier.
 
typedef struct _thread thread_t
 forward declaration for thread_t, defined in thread.h
 
typedef void(* sched_callback_t) (kernel_pid_t active, kernel_pid_t next)
 Scheduler run callback. More...
 

Functions

static int pid_is_valid (kernel_pid_t pid)
 Determine if the given pid is valid. More...
 
thread_tsched_run (void)
 Triggers the scheduler to schedule the next thread. More...
 
void sched_set_status (thread_t *process, thread_status_t status)
 Set the status of the specified process. More...
 
void sched_switch (uint16_t other_prio)
 Yield if appropriate. More...
 
NORETURN void cpu_switch_context_exit (void)
 Call context switching at thread exit.
 
NORETURN void sched_task_exit (void)
 Removes thread from scheduler and set status to STATUS_STOPPED.
 
void sched_arch_idle (void)
 Set CPU to idle mode (CPU dependent) More...
 
void sched_register_cb (sched_callback_t callback)
 Register a callback that will be called on every scheduler run. More...
 
static void sched_runq_advance (uint8_t prio)
 Advance a runqueue. More...
 
void sched_runq_callback (uint8_t prio)
 Scheduler runqueue (change) callback. More...
 
static int sched_runq_is_empty (uint8_t prio)
 Tell if the number of threads in a runqueue is 0. More...
 
static int sched_runq_exactly_one (uint8_t prio)
 Tell if the number of threads in a runqueue is 1. More...
 
static int sched_runq_more_than_one (uint8_t prio)
 Tell if the number of threads in a runqueue greater than 1. More...
 

Variables

volatile unsigned int sched_context_switch_request
 Flag indicating whether a context switch is necessary after handling an interrupt. More...
 
volatile thread_tsched_threads [KERNEL_PID_LAST+1]
 Thread table.
 
volatile int sched_num_threads
 Number of running (non-terminated) threads.
 
clist_node_t sched_runqueues [SCHED_PRIO_LEVELS]
 List of runqueues per priority level.
 

Helpers to work with thread states

#define STATUS_ON_RUNQUEUE   STATUS_RUNNING
 to check if on run queue: st >= STATUS_ON_RUNQUEUE

 
#define STATUS_NOT_FOUND   ((thread_status_t)-1)
 Describes an illegal thread status.
 

Thread states supported by RIOT

  Keep in sync with OpenOCD src/rtos/riot.c
enum  thread_status_t {
  STATUS_STOPPED , STATUS_ZOMBIE , STATUS_SLEEPING , STATUS_MUTEX_BLOCKED ,
  STATUS_RECEIVE_BLOCKED , STATUS_SEND_BLOCKED , STATUS_REPLY_BLOCKED , STATUS_FLAG_BLOCKED_ANY ,
  STATUS_FLAG_BLOCKED_ALL , STATUS_MBOX_BLOCKED , STATUS_COND_BLOCKED , STATUS_RUNNING ,
  STATUS_PENDING , STATUS_NUMOF
}