1.1 --- a/src/os/bsd/vm/os_bsd.cpp Wed May 28 12:07:21 2014 -0700
1.2 +++ b/src/os/bsd/vm/os_bsd.cpp Thu May 29 09:56:06 2014 -0700
1.3 @@ -123,12 +123,19 @@
1.4 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
1.5
1.6 #define LARGEPAGES_BIT (1 << 6)
1.7 +
1.8 +PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
1.9 +
1.10 ////////////////////////////////////////////////////////////////////////////////
1.11 // global variables
1.12 julong os::Bsd::_physical_memory = 0;
1.13
1.14 -
1.15 +#ifdef __APPLE__
1.16 +mach_timebase_info_data_t os::Bsd::_timebase_info = {0, 0};
1.17 +volatile uint64_t os::Bsd::_max_abstime = 0;
1.18 +#else
1.19 int (*os::Bsd::_clock_gettime)(clockid_t, struct timespec *) = NULL;
1.20 +#endif
1.21 pthread_t os::Bsd::_main_thread;
1.22 int os::Bsd::_page_size = -1;
1.23
1.24 @@ -986,13 +993,15 @@
1.25 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1.26 }
1.27
1.28 +#ifndef __APPLE__
1.29 #ifndef CLOCK_MONOTONIC
1.30 #define CLOCK_MONOTONIC (1)
1.31 #endif
1.32 +#endif
1.33
1.34 #ifdef __APPLE__
1.35 void os::Bsd::clock_init() {
1.36 - // XXXDARWIN: Investigate replacement monotonic clock
1.37 + mach_timebase_info(&_timebase_info);
1.38 }
1.39 #else
1.40 void os::Bsd::clock_init() {
1.41 @@ -1007,10 +1016,38 @@
1.42 #endif
1.43
1.44
1.45 +#ifdef __APPLE__
1.46 +
1.47 +jlong os::javaTimeNanos() {
1.48 + const uint64_t tm = mach_absolute_time();
1.49 + const uint64_t now = (tm * Bsd::_timebase_info.numer) / Bsd::_timebase_info.denom;
1.50 + const uint64_t prev = Bsd::_max_abstime;
1.51 + if (now <= prev) {
1.52 + return prev; // same or retrograde time;
1.53 + }
1.54 + const uint64_t obsv = Atomic::cmpxchg(now, (volatile jlong*)&Bsd::_max_abstime, prev);
1.55 + assert(obsv >= prev, "invariant"); // Monotonicity
1.56 + // If the CAS succeeded then we're done and return "now".
1.57 + // If the CAS failed and the observed value "obsv" is >= now then
1.58 + // we should return "obsv". If the CAS failed and now > obsv > prv then
1.59 + // some other thread raced this thread and installed a new value, in which case
1.60 + // we could either (a) retry the entire operation, (b) retry trying to install now
1.61 + // or (c) just return obsv. We use (c). No loop is required although in some cases
1.62 + // we might discard a higher "now" value in deference to a slightly lower but freshly
1.63 + // installed obsv value. That's entirely benign -- it admits no new orderings compared
1.64 + // to (a) or (b) -- and greatly reduces coherence traffic.
1.65 + // We might also condition (c) on the magnitude of the delta between obsv and now.
1.66 + // Avoiding excessive CAS operations to hot RW locations is critical.
1.67 + // See https://blogs.oracle.com/dave/entry/cas_and_cache_trivia_invalidate
1.68 + return (prev == obsv) ? now : obsv;
1.69 +}
1.70 +
1.71 +#else // __APPLE__
1.72 +
1.73 jlong os::javaTimeNanos() {
1.74 if (Bsd::supports_monotonic_clock()) {
1.75 struct timespec tp;
1.76 - int status = Bsd::clock_gettime(CLOCK_MONOTONIC, &tp);
1.77 + int status = Bsd::_clock_gettime(CLOCK_MONOTONIC, &tp);
1.78 assert(status == 0, "gettime error");
1.79 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1.80 return result;
1.81 @@ -1023,6 +1060,8 @@
1.82 }
1.83 }
1.84
1.85 +#endif // __APPLE__
1.86 +
1.87 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1.88 if (Bsd::supports_monotonic_clock()) {
1.89 info_ptr->max_value = ALL_64_BITS;
1.90 @@ -2351,7 +2390,6 @@
1.91 (!FLAG_IS_DEFAULT(UseLargePages) ||
1.92 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
1.93 );
1.94 - char msg[128];
1.95
1.96 // Create a large shared memory region to attach to based on size.
1.97 // Currently, size is the total size of the heap
1.98 @@ -2372,8 +2410,7 @@
1.99 // coalesce into large pages. Try to reserve large pages when
1.100 // the system is still "fresh".
1.101 if (warn_on_failure) {
1.102 - jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
1.103 - warning(msg);
1.104 + warning("Failed to reserve shared memory (errno = %d).", errno);
1.105 }
1.106 return NULL;
1.107 }
1.108 @@ -2390,8 +2427,7 @@
1.109
1.110 if ((intptr_t)addr == -1) {
1.111 if (warn_on_failure) {
1.112 - jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
1.113 - warning(msg);
1.114 + warning("Failed to attach shared memory (errno = %d).", err);
1.115 }
1.116 return NULL;
1.117 }
1.118 @@ -3890,6 +3926,7 @@
1.119 return true;
1.120 }
1.121
1.122 +ATTRIBUTE_PRINTF(3, 0)
1.123 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
1.124 return ::vsnprintf(buf, count, format, args);
1.125 }
