diff options
| -rw-r--r-- | Changes | 1 | ||||
| -rw-r--r-- | ecb.h | 24 | ||||
| -rw-r--r-- | eio.c | 10 |
3 files changed, 22 insertions, 13 deletions
@@ -59,4 +59,5 @@ TODO: fadvise request - incorporated some mingw32 changes by traviscline. - added syncfs support, using direct syscall. - set thread name on linux (ps -L/Hcx, top, gdb). + - remove useless use of volatile variables. @@ -69,12 +69,12 @@ #if ECB_GCC_VERSION(2,5) #if __x86 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory") - #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE - #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE /* better be safe than sorry */ + #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE /* non-lock xchg might be enough */ + #define ECB_MEMORY_FENCE_RELEASE do { } while (0) /* unlikely to change in future cpus */ #elif __amd64 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mfence" : : : "memory") #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("lfence" : : : "memory") - #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("sfence") + #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("sfence") /* play safe - not needed in any current cpu */ #endif #endif #endif @@ -84,19 +84,27 @@ #define ECB_MEMORY_FENCE __sync_synchronize () #define ECB_MEMORY_FENCE_ACQUIRE ({ char dummy = 0; __sync_lock_test_and_set (&dummy, 1); }) #define ECB_MEMORY_FENCE_RELEASE ({ char dummy = 1; __sync_lock_release (&dummy ); }) - #elif _MSC_VER >= 1400 && 0 /* TODO: only true when using volatiles */ - #define ECB_MEMORY_FENCE do { } while (0) - #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE - #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE + #elif _MSC_VER >= 1400 /* VC++ 2005 */ + #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier) + #define ECB_MEMORY_FENCE _ReadWriteBarrier () + #define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier () /* according to msdn, _ReadBarrier is not a load fence */ + #define ECB_MEMORY_FENCE_RELEASE _WriteBarrier () #elif defined(_WIN32) #include <WinNT.h> - #define ECB_MEMORY_FENCE MemoryBarrier () + #define ECB_MEMORY_FENCE MemoryBarrier () /* actually just xchg on x86... scary */ #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE #endif #endif #ifndef ECB_MEMORY_FENCE + /* + * if you get undefined symbol references to pthread_mutex_lock, + * or failure to find pthread.h, then you should implement + * the ECB_MEMORY_FENCE operations for your cpu/compiler + * OR proide pthread.h and link against the posix thread library + * of your system. + */ #include <pthread.h> static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER; @@ -326,11 +326,11 @@ static void (*done_poll_cb) (void); static unsigned int max_poll_time; /* reslock */ static unsigned int max_poll_reqs; /* reslock */ -static volatile unsigned int nreqs; /* reqlock */ -static volatile unsigned int nready; /* reqlock */ -static volatile unsigned int npending; /* reqlock */ -static volatile unsigned int max_idle = 4; /* maximum number of threads that can idle indefinitely */ -static volatile unsigned int idle_timeout = 10; /* number of seconds after which an idle threads exit */ +static unsigned int nreqs; /* reqlock */ +static unsigned int nready; /* reqlock */ +static unsigned int npending; /* reqlock */ +static unsigned int max_idle = 4; /* maximum number of threads that can idle indefinitely */ +static unsigned int idle_timeout = 10; /* number of seconds after which an idle threads exit */ static xmutex_t wrklock; static xmutex_t reslock; |