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Comparing libev/ev.c (file contents):
Revision 1.391 by root, Thu Aug 4 13:57:16 2011 UTC vs.
Revision 1.396 by root, Wed Aug 24 16:13:17 2011 UTC

… …
537 537
538/* ECB_NO_THREADS - ecb is not used by multiple threads, ever */ 538/* ECB_NO_THREADS - ecb is not used by multiple threads, ever */
539/* ECB_NO_SMP - ecb might be used in multiple threads, but only on a single cpu */ 539/* ECB_NO_SMP - ecb might be used in multiple threads, but only on a single cpu */
540 540
541#if ECB_NO_THREADS || ECB_NO_SMP 541#if ECB_NO_THREADS || ECB_NO_SMP
542 #define ECB_MEMORY_FENCE do { } while (0) 542 #define ECB_MEMORY_FENCE do { } while (0)
543 #define ECB_MEMORY_FENCE_ACQUIRE do { } while (0)
544 #define ECB_MEMORY_FENCE_RELEASE do { } while (0)
545#endif 543#endif
546 544
547#ifndef ECB_MEMORY_FENCE 545#ifndef ECB_MEMORY_FENCE
548 #if ECB_GCC_VERSION(2,5) 546 #if ECB_GCC_VERSION(2,5)
549 #if __x86 547 #if __i386__
550 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory") 548 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory")
551 #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE /* non-lock xchg might be enough */ 549 #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE /* non-lock xchg might be enough */
552 #define ECB_MEMORY_FENCE_RELEASE do { } while (0) /* unlikely to change in future cpus */ 550 #define ECB_MEMORY_FENCE_RELEASE do { } while (0) /* unlikely to change in future cpus */
553 #elif __amd64 551 #elif __amd64
554 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mfence" : : : "memory") 552 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mfence" : : : "memory")
555 #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("lfence" : : : "memory") 553 #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("lfence" : : : "memory")
556 #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("sfence") /* play safe - not needed in any current cpu */ 554 #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("sfence") /* play safe - not needed in any current cpu */
555 #elif __powerpc__ || __ppc__ || __powerpc64__ || __ppc64__
556 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("sync" : : : "memory")
557 #elif defined(__ARM_ARCH_6__ ) || defined(__ARM_ARCH_6J__ ) \
558 || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6ZK__)
559 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mcr p15,0,%0,c7,c10,5" : : "r" (0) : "memory")
560 #elif defined(__ARM_ARCH_7__ ) || defined(__ARM_ARCH_7A__ ) \
561 || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7R__ )
562 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("dmb" : : : "memory")
557 #endif 563 #endif
558 #endif 564 #endif
559#endif 565#endif
560 566
561#ifndef ECB_MEMORY_FENCE 567#ifndef ECB_MEMORY_FENCE
562 #if ECB_GCC_VERSION(4,4) 568 #if ECB_GCC_VERSION(4,4) || defined(__INTEL_COMPILER)
563 #define ECB_MEMORY_FENCE __sync_synchronize () 569 #define ECB_MEMORY_FENCE __sync_synchronize ()
564 #define ECB_MEMORY_FENCE_ACQUIRE ({ char dummy = 0; __sync_lock_test_and_set (&dummy, 1); }) 570 /*#define ECB_MEMORY_FENCE_ACQUIRE ({ char dummy = 0; __sync_lock_test_and_set (&dummy, 1); }) */
565 #define ECB_MEMORY_FENCE_RELEASE ({ char dummy = 1; __sync_lock_release (&dummy ); }) 571 /*#define ECB_MEMORY_FENCE_RELEASE ({ char dummy = 1; __sync_lock_release (&dummy ); }) */
566 #elif _MSC_VER >= 1400 /* VC++ 2005 */ 572 #elif _MSC_VER >= 1400 /* VC++ 2005 */
567 #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier) 573 #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier)
568 #define ECB_MEMORY_FENCE _ReadWriteBarrier () 574 #define ECB_MEMORY_FENCE _ReadWriteBarrier ()
569 #define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier () /* according to msdn, _ReadBarrier is not a load fence */ 575 #define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier () /* according to msdn, _ReadBarrier is not a load fence */
570 #define ECB_MEMORY_FENCE_RELEASE _WriteBarrier () 576 #define ECB_MEMORY_FENCE_RELEASE _WriteBarrier ()
571 #elif defined(_WIN32) 577 #elif defined(_WIN32)
572 #include <WinNT.h> 578 #include <WinNT.h>
573 #define ECB_MEMORY_FENCE MemoryBarrier () /* actually just xchg on x86... scary */ 579 #define ECB_MEMORY_FENCE MemoryBarrier () /* actually just xchg on x86... scary */
574 #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
575 #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
576 #endif 580 #endif
577#endif 581#endif
578 582
579#ifndef ECB_MEMORY_FENCE 583#ifndef ECB_MEMORY_FENCE
584 #if !ECB_AVOID_PTHREADS
580 /* 585 /*
581 * if you get undefined symbol references to pthread_mutex_lock, 586 * if you get undefined symbol references to pthread_mutex_lock,
582 * or failure to find pthread.h, then you should implement 587 * or failure to find pthread.h, then you should implement
583 * the ECB_MEMORY_FENCE operations for your cpu/compiler 588 * the ECB_MEMORY_FENCE operations for your cpu/compiler
584 * OR provide pthread.h and link against the posix thread library 589 * OR provide pthread.h and link against the posix thread library
585 * of your system. 590 * of your system.
586 */ 591 */
587 #include <pthread.h> 592 #include <pthread.h>
588 #define ECB_NEEDS_PTHREADS 1 593 #define ECB_NEEDS_PTHREADS 1
589 #define ECB_MEMORY_FENCE_NEEDS_PTHREADS 1 594 #define ECB_MEMORY_FENCE_NEEDS_PTHREADS 1
590 595
591 static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER; 596 static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER;
592 #define ECB_MEMORY_FENCE do { pthread_mutex_lock (&ecb_mf_lock); pthread_mutex_unlock (&ecb_mf_lock); } while (0) 597 #define ECB_MEMORY_FENCE do { pthread_mutex_lock (&ecb_mf_lock); pthread_mutex_unlock (&ecb_mf_lock); } while (0)
598 #endif
599#endif
600
601#if !defined(ECB_MEMORY_FENCE_ACQUIRE) && defined(ECB_MEMORY_FENCE)
593 #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE 602 #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
603#endif
604
605#if !defined(ECB_MEMORY_FENCE_RELEASE) && defined(ECB_MEMORY_FENCE)
594 #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE 606 #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
595#endif 607#endif
596 608
597/*****************************************************************************/ 609/*****************************************************************************/
598 610
… …
845#endif 857#endif
846 858
847#endif 859#endif
848 860
849/* ECB.H END */ 861/* ECB.H END */
862
863#if ECB_MEMORY_FENCE_NEEDS_PTHREADS
864/* if your architetcure doesn't need memory fences, e.g. because it is
865 * single-cpu/core, or if you use libev in a project that doesn't use libev
866 * from multiple threads, then you can define ECB_AVOID_PTHREADS when compiling
867 * libev, in which casess the memory fences become nops.
868 * alternatively, you can remove this #error and link against libpthread,
869 * which will then provide the memory fences.
870 */
871# error "memory fences not defined for your architecture, please report"
872#endif
873
874#ifndef ECB_MEMORY_FENCE
875# define ECB_MEMORY_FENCE do { } while (0)
876# define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
877# define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
878#endif
850 879
851#define expect_false(cond) ecb_expect_false (cond) 880#define expect_false(cond) ecb_expect_false (cond)
852#define expect_true(cond) ecb_expect_true (cond) 881#define expect_true(cond) ecb_expect_true (cond)
853#define noinline ecb_noinline 882#define noinline ecb_noinline
854 883
… …
1754 1783
1755 if (pipe_write_wanted) 1784 if (pipe_write_wanted)
1756 { 1785 {
1757 int old_errno; 1786 int old_errno;
1758 1787
1759 pipe_write_skipped = 0; /* just an optimsiation, no fence needed */ 1788 pipe_write_skipped = 0; /* just an optimisation, no fence needed */
1760 1789
1761 old_errno = errno; /* save errno because write will clobber it */ 1790 old_errno = errno; /* save errno because write will clobber it */
1762 1791
1763#if EV_USE_EVENTFD 1792#if EV_USE_EVENTFD
1764 if (evfd >= 0) 1793 if (evfd >= 0)

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