diff options
Diffstat (limited to 'lib/libthr/thread/thr_mutex.c')
| -rw-r--r-- | lib/libthr/thread/thr_mutex.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/libthr/thread/thr_mutex.c b/lib/libthr/thread/thr_mutex.c index c08ee81..b1e6d0c 100644 --- a/lib/libthr/thread/thr_mutex.c +++ b/lib/libthr/thread/thr_mutex.c @@ -39,6 +39,8 @@ #include <string.h> #include <sys/param.h> #include <sys/queue.h> +#include <machine/cpu.h> +#include <machine/cpufunc.h> #include <pthread.h> #include "un-namespace.h" @@ -65,6 +67,12 @@ #endif /* + * For adaptive mutexes, how many times to spin doing trylock2 + * before entering the kernel to block + */ +#define MUTEX_ADAPTIVE_SPINS 200 + +/* * Prototypes */ int __pthread_mutex_init(pthread_mutex_t *mutex, @@ -355,6 +363,25 @@ mutex_lock_common(struct pthread *curthread, pthread_mutex_t *mutex, } else if (m->m_owner == curthread) { ret = mutex_self_lock(m, abstime); } else { + /* + * For adaptive mutexes, spin for a bit in the expectation + * that if the application requests this mutex type then + * the lock is likely to be released quickly and it is + * faster than entering the kernel + */ + if (m->m_type == PTHREAD_MUTEX_ADAPTIVE_NP) { + int count = MUTEX_ADAPTIVE_SPINS; + + while (count--) { + ret = _thr_umutex_trylock2(&m->m_lock, id); + if (ret == 0) + break; + cpu_spinwait(); + } + } + if (ret == 0) + goto done; + if (abstime == NULL) { ret = __thr_umutex_lock(&m->m_lock); } else if (__predict_false( @@ -372,6 +399,7 @@ mutex_lock_common(struct pthread *curthread, pthread_mutex_t *mutex, if (ret == EINTR) ret = ETIMEDOUT; } +done: if (ret == 0) { m->m_owner = curthread; /* Add to the list of owned mutexes: */ @@ -501,6 +529,7 @@ mutex_self_trylock(pthread_mutex_t m) switch (m->m_type) { case PTHREAD_MUTEX_ERRORCHECK: case PTHREAD_MUTEX_NORMAL: + case PTHREAD_MUTEX_ADAPTIVE_NP: ret = EBUSY; break; |
