diff options
| -rw-r--r-- | src/internal/pthread_impl.h | 2 | ||||
| -rw-r--r-- | src/thread/pthread_barrier_wait.c | 24 |
2 files changed, 14 insertions, 12 deletions
diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h index 82d62426..dd3863fc 100644 --- a/src/internal/pthread_impl.h +++ b/src/internal/pthread_impl.h @@ -77,7 +77,7 @@ struct __timer { #define _b_waiters __u.__i[1] #define _b_limit __u.__i[2] #define _b_count __u.__i[3] -#define _b_seq __u.__i[4] +#define _b_waiters2 __u.__i[4] #define _b_inst __u.__p[4] #include "pthread_arch.h" diff --git a/src/thread/pthread_barrier_wait.c b/src/thread/pthread_barrier_wait.c index 9b1edbf9..71f7b5fe 100644 --- a/src/thread/pthread_barrier_wait.c +++ b/src/thread/pthread_barrier_wait.c @@ -21,7 +21,6 @@ void __vm_unlock(void) static int pshared_barrier_wait(pthread_barrier_t *b) { int limit = (b->_b_limit & INT_MAX) + 1; - int seq; int ret = 0; int v, w; @@ -30,33 +29,36 @@ static int pshared_barrier_wait(pthread_barrier_t *b) while ((v=a_cas(&b->_b_lock, 0, limit))) __wait(&b->_b_lock, &b->_b_waiters, v, 0); - seq = b->_b_seq; - + /* Wait for <limit> threads to get to the barrier */ if (++b->_b_count == limit) { + a_store(&b->_b_count, 0); ret = PTHREAD_BARRIER_SERIAL_THREAD; - b->_b_seq++; - __wake(&b->_b_seq, -1, 0); + if (b->_b_waiters2) __wake(&b->_b_count, -1, 0); } else { a_store(&b->_b_lock, 0); if (b->_b_waiters) __wake(&b->_b_lock, 1, 0); - __wait(&b->_b_seq, 0, seq, 0); + while ((v=b->_b_count)>0) + __wait(&b->_b_count, &b->_b_waiters2, v, 0); } __vm_lock(+1); - if (a_fetch_add(&b->_b_count, -1)==1) { - b->_b_seq++; - __wake(&b->_b_seq, -1, 0); + /* Ensure all threads have a vm lock before proceeding */ + if (a_fetch_add(&b->_b_count, -1)==1-limit) { + a_store(&b->_b_count, 0); + if (b->_b_waiters2) __wake(&b->_b_count, -1, 0); } else { - __wait(&b->_b_seq, 0, seq+1, 0); + while ((v=b->_b_count)) + __wait(&b->_b_count, &b->_b_waiters2, v, 0); } /* Perform a recursive unlock suitable for self-sync'd destruction */ do { v = b->_b_lock; w = b->_b_waiters; - } while (a_cas(&b->_b_lock, v, v-1 & INT_MAX) != v); + } while (a_cas(&b->_b_lock, v, v==INT_MIN+1 ? 0 : v-1) != v); + /* Wake a thread waiting to reuse or destroy the barrier */ if (v==INT_MIN+1 || (v==1 && w)) __wake(&b->_b_lock, 1, 0); |