|
0
|
1 //========================================================================== |
|
|
2 // |
|
|
3 // bin_sem2.cxx |
|
|
4 // |
|
|
5 // Binary semaphore test 2 |
|
|
6 // |
|
|
7 //========================================================================== |
|
|
8 //####COPYRIGHTBEGIN#### |
|
|
9 // |
|
|
10 // ------------------------------------------- |
|
|
11 // The contents of this file are subject to the Cygnus eCos Public License |
|
|
12 // Version 1.0 (the "License"); you may not use this file except in |
|
|
13 // compliance with the License. You may obtain a copy of the License at |
|
|
14 // http://sourceware.cygnus.com/ecos |
|
|
15 // |
|
|
16 // Software distributed under the License is distributed on an "AS IS" |
|
|
17 // basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the |
|
|
18 // License for the specific language governing rights and limitations under |
|
|
19 // the License. |
|
|
20 // |
|
|
21 // The Original Code is eCos - Embedded Cygnus Operating System, released |
|
|
22 // September 30, 1998. |
|
|
23 // |
|
|
24 // The Initial Developer of the Original Code is Cygnus. Portions created |
|
|
25 // by Cygnus are Copyright (C) 1998 Cygnus Solutions. All Rights Reserved. |
|
|
26 // ------------------------------------------- |
|
|
27 // |
|
|
28 //####COPYRIGHTEND#### |
|
|
29 //========================================================================== |
|
|
30 //#####DESCRIPTIONBEGIN#### |
|
|
31 // |
|
|
32 // Author(s): nickg,dsm |
|
|
33 // Contributors: dsm |
|
|
34 // Date: 1998-03-10 |
|
|
35 // Description: |
|
|
36 // Dining philosophers test. Based on philo.cxx |
|
|
37 //####DESCRIPTIONEND#### |
|
|
38 |
|
|
39 #include <pkgconf/kernel.h> |
|
|
40 |
|
|
41 #include <cyg/kernel/sched.hxx> |
|
|
42 #include <cyg/kernel/thread.hxx> |
|
|
43 #include <cyg/kernel/thread.inl> |
|
|
44 #include <cyg/kernel/mutex.hxx> |
|
|
45 |
|
|
46 #include <cyg/kernel/sema.hxx> |
|
|
47 |
|
|
48 #include <cyg/infra/testcase.h> |
|
|
49 |
|
|
50 #include <cyg/kernel/sched.inl> |
|
|
51 |
|
|
52 #if defined(CYG_HAL_MIPS_SIM) |
|
|
53 // Reduce number of loops in simulated TX39 so that |
|
|
54 // it runs within the timeout. |
|
|
55 #define PHILO_LOOPS 100 |
|
|
56 #else |
|
|
57 |
|
|
58 #define PHILO_LOOPS 1000 |
|
|
59 |
|
|
60 #endif |
|
|
61 |
|
|
62 #define PHILOSOPHERS 15 |
|
|
63 #define NTHREADS PHILOSOPHERS |
|
|
64 #include "testaux.hxx" |
|
|
65 |
|
|
66 static Cyg_Binary_Semaphore chopstick[PHILOSOPHERS]; |
|
|
67 |
|
|
68 static char pstate[PHILOSOPHERS+1]; // state of each philosopher |
|
|
69 |
|
|
70 static cyg_ucount8 state_changes = 0; |
|
|
71 // state_changes keep track of number of changes to pstate so |
|
|
72 // we can exit after we've seen enough. |
|
|
73 |
|
|
74 |
|
|
75 static Cyg_Mutex pstate_mutex; |
|
|
76 static Cyg_Mutex cycle_mutex; |
|
|
77 |
|
|
78 static inline int left(cyg_count8 i) |
|
|
79 { |
|
|
80 return (0 == i) ? PHILOSOPHERS-1 : i-1 ; |
|
|
81 } |
|
|
82 static inline int right(cyg_count8 i) |
|
|
83 { |
|
|
84 return (PHILOSOPHERS == i+1) ? 0 : i+1 ; |
|
|
85 } |
|
|
86 |
|
|
87 void change_state(int id, char newstate) |
|
|
88 { |
|
|
89 if (PHILO_LOOPS == state_changes++) |
|
|
90 CYG_TEST_PASS_FINISH("Binary Semaphore 2 OK"); |
|
|
91 |
|
|
92 |
|
|
93 pstate_mutex.lock(); { |
|
|
94 pstate[id] = newstate; |
|
|
95 bool all_hungry = true; // until proved otherwise |
|
|
96 for(cyg_ucount8 i=0; i < PHILOSOPHERS; i++) { |
|
|
97 if('E' == pstate[i]) { |
|
|
98 CHECK('E' != pstate[left(i)]); |
|
|
99 CHECK('E' != pstate[right(i)]); |
|
|
100 } |
|
|
101 if('H' != pstate[i]) { |
|
|
102 all_hungry = false; |
|
|
103 } |
|
|
104 } |
|
|
105 // Theoretically it is possible for all the philosophers to be |
|
|
106 // hungry but not waiting on semaphores. But in practice this |
|
|
107 // means something is wrong. |
|
|
108 CHECK(false == all_hungry); |
|
|
109 } pstate_mutex.unlock(); |
|
|
110 } |
|
|
111 |
|
|
112 char get_state(int id) |
|
|
113 { |
|
|
114 pstate_mutex.lock(); |
|
|
115 |
|
|
116 char s = pstate[id]; |
|
|
117 |
|
|
118 pstate_mutex.unlock(); |
|
|
119 |
|
|
120 return s; |
|
|
121 } |
|
|
122 |
|
|
123 // ------------------------------------------------------------------------- |
|
|
124 // Thread to behave like a philosopher |
|
|
125 |
|
|
126 void Philosopher( CYG_ADDRESS id ) |
|
|
127 { |
|
|
128 Cyg_Thread *self = Cyg_Thread::self(); |
|
|
129 Cyg_Binary_Semaphore *first_stick = &chopstick[id]; |
|
|
130 Cyg_Binary_Semaphore *second_stick = &chopstick[(id+1)%PHILOSOPHERS]; |
|
|
131 |
|
|
132 CHECK( id >= 0 && id < PHILOSOPHERS); |
|
|
133 |
|
|
134 // Deadlock avoidance. The easiest way to make the philosophers |
|
|
135 // behave is to make each pick up the lowest numbered stick |
|
|
136 // first. This is how it works out anyway for all the philosophers |
|
|
137 // except the last, who must have his sticks swapped. |
|
|
138 |
|
|
139 if( id == PHILOSOPHERS-1 ) |
|
|
140 { |
|
|
141 Cyg_Binary_Semaphore *t = first_stick; |
|
|
142 first_stick = second_stick; |
|
|
143 second_stick = t; |
|
|
144 } |
|
|
145 |
|
|
146 |
|
|
147 // The following variable is shared by all philosophers. |
|
|
148 // It is incremented unprotected, but this does not matter |
|
|
149 // since it is only present to introduce a little variability |
|
|
150 // into the think and eat times. |
|
|
151 |
|
|
152 static int cycle = 0; |
|
|
153 |
|
|
154 for(;;) |
|
|
155 { |
|
|
156 // Think for a bit |
|
|
157 |
|
|
158 self->delay((id+cycle++)%12); // Cogito ergo sum... |
|
|
159 |
|
|
160 // I am now hungry, try to get the chopsticks |
|
|
161 change_state(id,'H'); |
|
|
162 |
|
|
163 // Get the sticks |
|
|
164 first_stick->wait(); |
|
|
165 second_stick->wait(); |
|
|
166 |
|
|
167 // Got them, now eat |
|
|
168 change_state(id,'E'); |
|
|
169 |
|
|
170 // Check that the world is as I think it is... |
|
|
171 CYG_TEST_CHECK( !first_stick->posted(), |
|
|
172 "Not got first stick"); |
|
|
173 CYG_TEST_CHECK( !second_stick->posted(), |
|
|
174 "Not got second stick"); |
|
|
175 CYG_TEST_CHECK( get_state(left(id)) != 'E', |
|
|
176 "Left neighbour also eating!!"); |
|
|
177 CYG_TEST_CHECK( get_state(right(id)) != 'E', |
|
|
178 "Right neighbour also eating!!"); |
|
|
179 |
|
|
180 self->delay((id+cycle++)%6); // munch munch |
|
|
181 |
|
|
182 // Finished eating, put down sticks. |
|
|
183 |
|
|
184 change_state(id,'T'); |
|
|
185 |
|
|
186 // put sticks back on table |
|
|
187 first_stick->post(); |
|
|
188 second_stick->post(); |
|
|
189 } |
|
|
190 } |
|
|
191 |
|
|
192 // ------------------------------------------------------------------------- |
|
|
193 |
|
|
194 void bin_sem2_main( void ) |
|
|
195 { |
|
|
196 CYG_TEST_INIT(); |
|
|
197 |
|
|
198 for( int i = 0; i < PHILOSOPHERS; i++ ) |
|
|
199 { |
|
|
200 pstate[i] = 'T'; // starting state |
|
|
201 new_thread(Philosopher, i); |
|
|
202 |
|
|
203 // make the matching chopstick present |
|
|
204 chopstick[i].post(); |
|
|
205 } |
|
|
206 |
|
|
207 Cyg_Scheduler::scheduler.start(); |
|
|
208 } |
|
|
209 |
|
|
210 externC void |
|
|
211 cyg_start( void ) |
|
|
212 { |
|
|
213 bin_sem2_main(); |
|
|
214 } |
|
|
215 // EOF bin_sem2.cxx |
