1 2 /* FIXME: this is basically a bad test as it is scheduling- 3 sensitive. Sometimes the output is: 4 5 child: new value 6 6 child: new value 10 7 done, x = 10 8 9 and sometimes 10 11 child: new value 10 12 done, x = 10 13 */ 14 15 #include <pthread.h> 16 #include <stdio.h> 17 #include <stdlib.h> 18 #include <unistd.h> 19 20 /* Simple test program, no race. Parent writes atomically to a counter 21 whilst child reads it. When counter reaches a prearranged value, 22 child joins back to parent. Parent (writer) uses hardware bus lock; 23 child is only reading and so does not need to use a bus lock. */ 24 25 #undef PLAT_x86_darwin 26 #undef PLAT_amd64_darwin 27 #undef PLAT_x86_linux 28 #undef PLAT_amd64_linux 29 #undef PLAT_ppc32_linux 30 #undef PLAT_ppc64_linux 31 #undef PLAT_arm_linux 32 #undef PLAT_arm64_linux 33 #undef PLAT_s390x_linux 34 #undef PLAT_mips32_linux 35 #undef PLAT_mips64_linux 36 #undef PLAT_tilegx_linux 37 #undef PLAT_x86_solaris 38 #undef PLAT_amd64_solaris 39 40 #if defined(__APPLE__) && defined(__i386__) 41 # define PLAT_x86_darwin 1 42 #elif defined(__APPLE__) && defined(__x86_64__) 43 # define PLAT_amd64_darwin 1 44 #elif defined(__linux__) && defined(__i386__) 45 # define PLAT_x86_linux 1 46 #elif defined(__linux__) && defined(__x86_64__) 47 # define PLAT_amd64_linux 1 48 #elif defined(__linux__) && defined(__powerpc__) && !defined(__powerpc64__) 49 # define PLAT_ppc32_linux 1 50 #elif defined(__linux__) && defined(__powerpc__) && defined(__powerpc64__) 51 # define PLAT_ppc64_linux 1 52 #elif defined(__linux__) && defined(__arm__) && !defined(__aarch64__) 53 # define PLAT_arm_linux 1 54 #elif defined(__linux__) && defined(__aarch64__) && !defined(__arm__) 55 # define PLAT_arm64_linux 1 56 #elif defined(__linux__) && defined(__s390x__) 57 # define PLAT_s390x_linux 1 58 #elif defined(__linux__) && defined(__mips__) 59 #if (__mips==64) 60 # define PLAT_mips64_linux 1 61 #else 62 # define PLAT_mips32_linux 1 63 #endif 64 #elif defined(__linux__) && defined(__tilegx__) 65 # define PLAT_tilegx_linux 1 66 #elif defined(__sun__) && defined(__i386__) 67 # define PLAT_x86_solaris 1 68 #elif defined(__sun__) && defined(__x86_64__) 69 # define PLAT_amd64_solaris 1 70 #endif 71 72 73 #if defined(PLAT_amd64_linux) || defined(PLAT_x86_linux) \ 74 || defined(PLAT_amd64_darwin) || defined(PLAT_x86_darwin) \ 75 || defined(PLAT_amd64_solaris) || defined(PLAT_x86_solaris) 76 # define INC(_lval,_lqual) \ 77 __asm__ __volatile__ ( \ 78 "lock ; incl (%0)" : /*out*/ : /*in*/"r"(&(_lval)) : "memory", "cc" ) 79 #elif defined(PLAT_ppc32_linux) || defined(PLAT_ppc64_linux) 80 # define INC(_lval,_lqual) \ 81 __asm__ __volatile__( \ 82 "1:\n" \ 83 " lwarx 15,0,%0\n" \ 84 " addi 15,15,1\n" \ 85 " stwcx. 15,0,%0\n" \ 86 " bne- 1b\n" \ 87 : /*out*/ : /*in*/ "b"(&(_lval)) \ 88 : /*trash*/ "r15", "cr0", "memory" \ 89 ) 90 #elif defined(PLAT_arm_linux) 91 # define INC(_lval,_lqual) \ 92 __asm__ __volatile__( \ 93 "1:\n" \ 94 " ldrex r8, [%0, #0]\n" \ 95 " add r8, r8, #1\n" \ 96 " strex r9, r8, [%0, #0]\n" \ 97 " cmp r9, #0\n" \ 98 " bne 1b\n" \ 99 : /*out*/ : /*in*/ "r"(&(_lval)) \ 100 : /*trash*/ "r8", "r9", "cc", "memory" \ 101 ); 102 #elif defined(PLAT_arm64_linux) 103 # define INC(_lval,_lqual) \ 104 __asm__ __volatile__( \ 105 "1:\n" \ 106 " ldxr w8, [%0, #0]\n" \ 107 " add w8, w8, #1\n" \ 108 " stxr w9, w8, [%0, #0]\n" \ 109 " cmp w9, #0\n" \ 110 " bne 1b\n" \ 111 : /*out*/ : /*in*/ "r"(&(_lval)) \ 112 : /*trash*/ "x8", "x9", "cc", "memory" \ 113 ); 114 #elif defined(PLAT_s390x_linux) 115 # define INC(_lval,_lqual) \ 116 __asm__ __volatile__( \ 117 "1: l 0,%0\n" \ 118 " lr 1,0\n" \ 119 " ahi 1,1\n" \ 120 " cs 0,1,%0\n" \ 121 " jl 1b\n" \ 122 : "+m" (_lval) :: "cc", "0","1" \ 123 ) 124 #elif defined(PLAT_mips32_linux) || defined(PLAT_mips64_linux) 125 # define INC(_lval,_lqual) \ 126 __asm__ __volatile__ ( \ 127 "L1xyzzy1" _lqual":\n" \ 128 " move $t0, %0\n" \ 129 " ll $t1, 0($t0)\n" \ 130 " addi $t1, $t1, 1\n" \ 131 " sc $t1, 0($t0)\n" \ 132 " beqz $t1, L1xyzzy1" _lqual \ 133 : /*out*/ : /*in*/ "r"(&(_lval)) \ 134 : /*trash*/ "t0", "t1", "memory" \ 135 ) 136 #elif defined(PLAT_tilegx_linux) 137 # define INC(_lval,_lqual) \ 138 if (sizeof(_lval) == 4) \ 139 __insn_fetchadd(&(_lval), 1); \ 140 else if(sizeof(_lval) == 8) \ 141 __insn_fetchadd(&(_lval), 1) 142 #else 143 # error "Fix Me for this platform" 144 #endif 145 146 147 148 #define LIMIT 10 149 150 volatile int x = 0; 151 152 void* child_fn ( void* arg ) 153 { 154 int q = 0; 155 int oldx = 0; 156 struct timespec ts = { 0, 1000 * 1000 }; 157 158 while (1) { 159 q = (x >= LIMIT); 160 if (x != oldx) { 161 oldx = x; 162 printf("child: new value %d\n", oldx); 163 fflush(stdout); 164 } 165 if (q) break; 166 nanosleep(&ts, 0); 167 } 168 return NULL; 169 } 170 171 int main ( void ) 172 { 173 pthread_t child; 174 int i; 175 176 if (pthread_create(&child, NULL, child_fn, NULL)) { 177 perror("pthread_create"); 178 exit(1); 179 } 180 181 for (i = 0; i < LIMIT; i++) { 182 INC(x, "main"); 183 if (i == 5) sleep(1); /* make sure child doesn't starve */ 184 } 185 186 if (pthread_join(child, NULL)) { 187 perror("pthread join"); 188 exit(1); 189 } 190 191 printf("done, x = %d\n", x); 192 193 return 0; 194 } 195
