Changeset 173
- Timestamp:
- May 30, 2011, 10:37:56 AM (13 years ago)
- File:
-
- 1 edited
-
trunk/softs/giet_tsar/drivers.c (modified) (10 diffs)
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trunk/softs/giet_tsar/drivers.c
r158 r173 128 128 //////////////////////////////////////////////////////////////////////////////////////// 129 129 130 in_unckdata int volatile _barrier_initial_value[8] = { 0,0,0,0,0,0,0,0 }; 131 in_unckdata int volatile _barrier_count[8] = { 0,0,0,0,0,0,0,0 }; 130 in_unckdata int volatile _barrier_initial_value[16] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }; 131 in_unckdata int volatile _barrier_count[16] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }; 132 in_unckdata int volatile _barrier_lock[16] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }; 132 133 133 134 //////////////////////////////////////////////////////////////////////////////////////// … … 179 180 // _procid() 180 181 // Access CP0 and returns processor ident 182 // No more than 1024 processors... 181 183 //////////////////////////////////////////////////////////////////////////////////////// 182 184 in_drivers unsigned int _procid() … … 184 186 unsigned int ret; 185 187 asm volatile( "mfc0 %0, $15, 1": "=r"(ret) ); 186 return (ret & 0x FF);188 return (ret & 0x3FF); 187 189 } 188 190 //////////////////////////////////////////////////////////////////////////////////////// … … 359 361 size_t ntasks = (size_t)&NB_TASKS; 360 362 size_t nprocs = (size_t)&NB_PROCS; 361 size_t nclusters = (size_t)&NB_CLUSTERS;362 unsigned int 363 size_t nclusters = (size_t)&NB_CLUSTERS; 364 unsigned int base = (unsigned int)&seg_tty_base; 363 365 unsigned int increment = _segment_increment(ntasks*TTY_SPAN*4); 364 366 size_t pid = _procid(); 365 size_t tid = _current_task_array[pid];366 367 int nwritten = 0; 368 size_t tid; 367 369 int i; 368 370 369 if( tid >= ntasks ) return -1; 371 if( ntasks == 0 ) tid = 0; 372 else tid = _current_task_array[pid]; 373 374 if( tid >= ntasks ) return -1; 370 375 if( pid >= nprocs*nclusters ) return -1; 371 376 … … 400 405 size_t nprocs = (size_t)&NB_PROCS; 401 406 size_t nclusters = (size_t)&NB_CLUSTERS; 402 unsigned int 407 unsigned int base = (unsigned int)&seg_tty_base; 403 408 unsigned int increment = _segment_increment(ntasks*TTY_SPAN*4); 404 409 size_t pid = _procid(); 405 size_t tid = _current_task_array[pid]; 406 407 if( length != 1) return -1; 408 if( pid >= nprocs*nclusters ) return -1; 409 if( tid >= ntasks ) return -1; 410 size_t tid; 411 412 if( pid > 7 ) tid = 0; 413 else tid = _current_task_array[pid]; 414 415 if( length != 1) return -1; 416 if( pid >= nprocs*nclusters ) return -1; 417 if( tid >= ntasks ) return -1; 410 418 411 419 tty_address = (char*)(base + increment + tid*TTY_SPAN*4); … … 436 444 { 437 445 int pid = _procid(); 438 int tid = _current_task_array[pid];439 446 int ntasks = (int)&NB_TASKS; 440 447 int nprocs = (int)&NB_PROCS; 441 448 int nclusters = (int)&NB_CLUSTERS; 442 449 int tty_index; 443 450 int tid; 451 452 if( pid > 7 ) tid = 0; 453 else tid = _current_task_array[pid]; 454 444 455 if( length != 1) return -1; 445 456 if( pid >= nprocs*nclusters ) return -1; … … 858 869 // _barrier_init() 859 870 // This function makes a cooperative initialisation of the barrier: 860 // Several tasks can try to initialize the barrier, but the initialisation 871 // - barrier_count[index] <= N 872 // - barrier_lock[index] <= 0 873 // All tasks try to initialize the barrier, but the initialisation 861 874 // is done by only one task, using LL/SC instructions. 875 // This cooperative initialisation is questionnable, 876 // bcause the barrier can ony be initialised once... 862 877 ////////////////////////////////////////////////////////////////////////////////////// 863 878 in_drivers int _barrier_init(unsigned int index, unsigned int value) … … 866 881 register int* pinit = (int*)&_barrier_initial_value[index]; 867 882 register int* pcount = (int*)&_barrier_count[index]; 883 register int* plock = (int*)&_barrier_lock[index]; 868 884 869 885 if ( index > 7 ) return 1; … … 871 887 // parallel initialisation using atomic instructions LL/SC 872 888 asm volatile ("_barrier_init_test: \n" 873 "ll $2, 0(%0) \n" // read initial value889 "ll $2, 0(%0) \n" // read barrier_inital_value 874 890 "bnez $2, _barrier_init_done \n" 875 "move $3, % 2\n"876 "sc $3, 0(%0) \n" // try to write initialvalue891 "move $3, %3 \n" 892 "sc $3, 0(%0) \n" // try to write barrier_initial_value 877 893 "beqz $3, _barrier_init_test \n" 878 "move $3, %2 \n" 879 "sw $3, 0(%1) \n" // write count 894 "move $3, %3 \n" 895 "sw $3, 0(%1) \n" // barrier_count <= barrier_initial_value 896 "move $3, $0 \n" // 897 "sw $3, 0(%2) \n" // barrier_lock <= 0 880 898 "_barrier_init_done: \n" 881 ::"r"(pinit),"r"(pcount),"r"( value):"$2","$3");899 ::"r"(pinit),"r"(pcount),"r"(plock),"r"(value):"$2","$3"); 882 900 return 0 ; 883 901 } 884 902 ////////////////////////////////////////////////////////////////////////////////////// 885 903 // _barrier_wait() 886 // This blocking function uses a busy_wait technics (on the countervalue),904 // This blocking function uses a busy_wait technics (on the barrier_lock value), 887 905 // because the GIET does not support dynamic scheduling/descheduling of tasks. 888 // In the busy waiting state, each task uses a pseudo-random delay between 889 // two successive read of the barrier counter in order to avoid bus saturation. 890 // the average delay is about 1000 cycles. 891 // There is at most 8 independant barriers, and an error is returned 892 // if the barrier index is larger than 7. 906 // The barrier state is actually defined by two variables: 907 // _barrier_count[index] define the number of particpants that are waiting 908 // _barrier_lock[index] define the bool variable whose value is polled 909 // The last participant change the value of _barrier_lock[index] to release the barrier... 910 // There is at most 16 independant barriers, and an error is returned 911 // if the barrier index is larger than 15. 893 912 ////////////////////////////////////////////////////////////////////////////////////// 894 913 in_drivers int _barrier_wait(unsigned int index) 895 914 { 896 915 register int* pcount = (int*)&_barrier_count[index]; 897 register int maxcount = _barrier_initial_value[index];898 916 register int count; 899 917 900 if ( index > 7 ) return 1; 901 902 // parallel decrement barrier counter using atomic instructions LL/SC 903 // input : pointer on the barrier counter 904 // output : counter value 918 int lock = _barrier_lock[index]; 919 920 if ( index > 15 ) return 1; 921 922 // parallel decrement _barrier_count[index] using atomic instructions LL/SC 923 // input : pointer on _barrier_count[index] 924 // output : count = _barrier_count[index] (before decrementation) 905 925 asm volatile ("_barrier_decrement: \n" 906 926 "ll %0, 0(%1) \n" … … 910 930 :"=r"(count):"r"(pcount):"$2","$3"); 911 931 912 // the last task re-initializes the barrier counter913 // to the max value, waking up all other waiting tasks932 // the last task re-initializes the barrier_ count variable 933 // and the barrier_lock variable, waking up all other waiting tasks 914 934 915 935 if ( count == 1 ) // last task 916 936 { 917 *pcount = maxcount; 918 return 0; 937 _barrier_count[index] = _barrier_initial_value[index]; 938 asm volatile( "sync" ); 939 _barrier_lock[index] = (lock == 0) ? 1 : 0; 940 return 0 ; 919 941 } 920 942 else // other tasks 921 943 { 922 while ( *pcount != maxcount) { } // busy waiting944 while ( lock == _barrier_lock[index] ) { } // busy waiting 923 945 return 0 ; 924 946 }
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