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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 | /* * Copyright (c) 2011-2016 Wind River Systems, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /** * @file * * Dining philosophers demo for unified kernel. * * The demo can be configured to use different object types for its * synchronization: SEMAPHORES, MUTEXES, STACKS, FIFOS and LIFOS. To configure * a specific object, set the value of FORKS to one of these. * * By default, the demo uses MUTEXES. * * The demo can also be configured to work with static objects or dynamic * objects. The behaviour will change depending if STATIC_OBJS is set to 0 or * 1. * * By default, the demo uses dynamic objects. * * The demo can be configured to work with threads of the same priority or * not. If using different priorities, two threads will be cooperative * threads, and the other four will be preemtible threads; if using one * priority, there will be six preemtible threads of priority 0. This is * changed via SAME_PRIO. * * By default, the demo uses different priorities. * * The number of threads is set via NUM_PHIL. The demo has only been tested * with six threads. In theory it should work with any number of threads, but * not without making changes to the forks[] array in the phil_obj_abstract.h * header file. */ #include <zephyr.h> #if defined(CONFIG_STDOUT_CONSOLE) #include <stdio.h> #else #include <misc/printk.h> #endif #include <misc/__assert.h> #define SEMAPHORES 1 #define MUTEXES 2 #define STACKS 3 #define FIFOS 4 #define LIFOS 5 /**************************************/ /* control the behaviour of the demo **/ #ifndef DEBUG_PRINTF #define DEBUG_PRINTF 0 #endif #ifndef NUM_PHIL #define NUM_PHIL 6 #endif #ifndef STATIC_OBJS #define STATIC_OBJS 0 #endif #ifndef FORKS #define FORKS MUTEXES #if 0 #define FORKS SEMAPHORES #define FORKS STACKS #define FORKS FIFOS #define FORKS LIFOS #endif #endif #define SAME_PRIO 0 /* end - control behaviour of the demo */ /***************************************/ #define STACK_SIZE 1024 /* * There are multiple tasks doing printfs and they may conflict. * Therefore use puts() instead of printf(). */ #if defined(CONFIG_STDOUT_CONSOLE) #define PRINTF(...) { char output[256]; \ sprintf(output, __VA_ARGS__); puts(output); } #else #define PRINTF(...) printk(__VA_ARGS__) #endif #if DEBUG_PRINTF #define PR_DEBUG PRINTF #else #define PR_DEBUG(...) #endif #include "phil_obj_abstract.h" #define fork(x) (forks[x]) static void set_phil_state_pos(int id) { #if !DEBUG_PRINTF PRINTF("\x1b[%d;%dH", id + 1, 1); #endif } #include <stdarg.h> static void print_phil_state(int id, const char *fmt, int32_t delay) { int prio = k_thread_priority_get(k_current_get()); set_phil_state_pos(id); PRINTF("Philosopher %d [%s:%s%d] ", id, prio < 0 ? "C" : "P", prio < 0 ? "" : " ", prio); if (delay) { PRINTF(fmt, delay < 1000 ? " " : "", delay); } else { PRINTF(fmt); } PRINTF("\n"); } static int32_t get_random_delay(int id) { /* * The random delay is in tenth of seconds, and is based on the * philosopher's ID and the current uptime to create some * pseudo-randomness. It produces a value between 0 and 1500 ms. */ int32_t tenth_of_sec = (k_uptime_get_32()/100 * (id + 1)) & 0x1f; /* add 1 since we want a delay of at least 100ms */ int32_t ms = (tenth_of_sec + 1) * 100; return ms; } static inline int is_last_philosopher(int id) { return id == (NUM_PHIL - 1); } void philosopher(void *id, void *unused1, void *unused2) { ARG_UNUSED(unused1); ARG_UNUSED(unused2); fork_t fork1; fork_t fork2; int my_id = (int)id; /* Djkstra's solution: always pick up the lowest numbered fork first */ if (is_last_philosopher(my_id)) { fork1 = fork(0); fork2 = fork(my_id); } else { fork1 = fork(my_id); fork2 = fork(my_id + 1); } while (1) { int32_t delay; print_phil_state(my_id, " STARVING ", 0); take(fork1); print_phil_state(my_id, " HOLDING ONE FORK ", 0); take(fork2); delay = get_random_delay(my_id); print_phil_state(my_id, " EATING [ %s%d ms ] ", delay); k_sleep(delay); drop(fork2); print_phil_state(my_id, " DROPPED ONE FORK ", 0); drop(fork1); delay = get_random_delay(my_id); print_phil_state(my_id, " THINKING [ %s%d ms ] ", delay); k_sleep(delay); } } static int new_prio(int phil) { #if SAME_PRIO return 0; #else return -(phil - (NUM_PHIL/2)); #endif } static void init_objects(void) { #if !STATIC_OBJS for (int i = 0; i < NUM_PHIL; i++) { fork_init(fork(i)); } #endif } static void start_threads(void) { /* create two fibers (prios -2/-1) and four tasks: (prios 0-3) */ for (int i = 0; i < NUM_PHIL; i++) { int prio = new_prio(i); k_thread_spawn(&stacks[i][0], STACK_SIZE, philosopher, (void *)i, NULL, NULL, prio, 0, 0); } } #define DEMO_DESCRIPTION \ "\x1b[2J\x1b[15;1H" \ "Demo Description\n" \ "----------------\n" \ "An implementation of a solution to the Dining Philosophers\n" \ "problem (a classic multi-thread synchronization problem).\n" \ "This particular implementation demonstrates the usage of multiple\n" \ "preemptible and cooperative threads of differing priorities, as\n" \ "well as %s %s and thread sleeping.\n", obj_init_type, fork_type_str static void display_demo_description(void) { #if !DEBUG_PRINTF PRINTF(DEMO_DESCRIPTION); #endif } void main(void) { display_demo_description(); init_objects(); start_threads(); } |