John Bailey / RoundRobin

Simple round-robin scheduler for mbed

Overview

This library provides simple round-robin scheduling based on the mbed-os.

Why would you want to use this?

  • Tasks are not run from within interrupt sub-routines (as they are using Tickers)
  • Ordering/priority of tasks is deterministic (rate monotonic)

It's not rocket science, just a handy wrapper around the RTOS functions.

Example

#define BASE_RATE 0.1f
#define TASK1_MULTIPLIER 1
#define TASK2_MULTIPLIER 2
....
    RoundRobin::instance()->SetBaseRate( BASE_RATE );
    RoundRobin::instance()->addTask( TASK1_MULTIPLIER, lcdRefresh );
    RoundRobin::instance()->addTask( TASK2_MULTIPLIER, watchButtons );

RoundRobin.hpp@1:549bc1cd1f3d, 2017-07-29 (annotated)

Committer:
johnb
Date:
Sat Jul 29 12:17:31 2017 +0000
Revision:
1:549bc1cd1f3d
Parent:
0:a8c603b939a7 
Remove mbed-os lib to prevent clashes when it's also included by the program

Who changed what in which revision?

UserRevisionLine numberNew contents of line
johnb 0:a8c603b939a7 1 /* @brief Round Robin scheduler for mbed
johnb 0:a8c603b939a7 2
johnb 0:a8c603b939a7 3 @author John Bailey
johnb 0:a8c603b939a7 4
johnb 0:a8c603b939a7 5 @copyright Copyright 2017 John Bailey
johnb 0:a8c603b939a7 6
johnb 0:a8c603b939a7 7 @section LICENSE
johnb 0:a8c603b939a7 8
johnb 0:a8c603b939a7 9 Licensed under the Apache License, Version 2.0 (the "License");
johnb 0:a8c603b939a7 10 you may not use this file except in compliance with the License.
johnb 0:a8c603b939a7 11 You may obtain a copy of the License at
johnb 0:a8c603b939a7 12
johnb 0:a8c603b939a7 13 http://www.apache.org/licenses/LICENSE-2.0
johnb 0:a8c603b939a7 14
johnb 0:a8c603b939a7 15 Unless required by applicable law or agreed to in writing, software
johnb 0:a8c603b939a7 16 distributed under the License is distributed on an "AS IS" BASIS,
johnb 0:a8c603b939a7 17 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
johnb 0:a8c603b939a7 18 See the License for the specific language governing permissions and
johnb 0:a8c603b939a7 19 limitations under the License.
johnb 0:a8c603b939a7 20 */
johnb 0:a8c603b939a7 21
johnb 0:a8c603b939a7 22 #if !defined ROUNDROBIN_HPP
johnb 0:a8c603b939a7 23 #define ROUNDROBIN_HPP
johnb 0:a8c603b939a7 24
johnb 0:a8c603b939a7 25 #include "rtos.h"
johnb 0:a8c603b939a7 26 #include <map>
johnb 0:a8c603b939a7 27
johnb 0:a8c603b939a7 28 class RoundRobin
johnb 0:a8c603b939a7 29 {
johnb 0:a8c603b939a7 30 protected:
johnb 0:a8c603b939a7 31 EventQueue eventQueue;
johnb 0:a8c603b939a7 32 Thread* thread;
johnb 0:a8c603b939a7 33 Ticker ticker;
johnb 0:a8c603b939a7 34 static RoundRobin *p_instance;
johnb 0:a8c603b939a7 35
johnb 0:a8c603b939a7 36 RoundRobin();
johnb 0:a8c603b939a7 37 static void EventTrigger( void );
johnb 0:a8c603b939a7 38
johnb 0:a8c603b939a7 39 class TaskEntry
johnb 0:a8c603b939a7 40 {
johnb 0:a8c603b939a7 41 void (*fn)( void );
johnb 0:a8c603b939a7 42 unsigned counter;
johnb 0:a8c603b939a7 43
johnb 0:a8c603b939a7 44 public:
johnb 0:a8c603b939a7 45 TaskEntry( void (*p_fn)( void ) ) : fn(p_fn),counter(0) {}
johnb 0:a8c603b939a7 46 void tick( void ) { counter++; }
johnb 0:a8c603b939a7 47 void triggerIfNeeded( unsigned multiplier )
johnb 0:a8c603b939a7 48 {
johnb 0:a8c603b939a7 49 if( multiplier == counter )
johnb 0:a8c603b939a7 50 {
johnb 0:a8c603b939a7 51 fn();
johnb 0:a8c603b939a7 52 counter = 0;
johnb 0:a8c603b939a7 53 }
johnb 0:a8c603b939a7 54 }
johnb 0:a8c603b939a7 55 };
johnb 0:a8c603b939a7 56
johnb 0:a8c603b939a7 57 static std::multimap<unsigned,TaskEntry> p_taskList;
johnb 0:a8c603b939a7 58
johnb 0:a8c603b939a7 59 public:
johnb 0:a8c603b939a7 60 virtual ~RoundRobin();
johnb 0:a8c603b939a7 61
johnb 0:a8c603b939a7 62 static RoundRobin* instance( void );
johnb 0:a8c603b939a7 63
johnb 0:a8c603b939a7 64 static bool addTask( unsigned p_multiplier, void (*p_fn)(void) );
johnb 0:a8c603b939a7 65
johnb 0:a8c603b939a7 66 void SetBaseRate( const float p_rate );
johnb 0:a8c603b939a7 67 };
johnb 0:a8c603b939a7 68
johnb 0:a8c603b939a7 69 #endif