Fix: use clock_get_time for caa_get_cycles fallback on MacOSX

Use clock_get_time as fallback to read time for caa_get_cycles on
MacOSX. It should not matter much in practice, since x86 uses the cycle
counter.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/configure.ac b/configure.ac
index b3096c6d45ca492d781ff35ff059868066fe260b..cf9964b45a2a489427483dc1647abb0a2f196fec 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -25,6 +25,7 @@ AH_TEMPLATE([CONFIG_RCU_HAVE_FUTEX], [Defined when on a system with futex suppor
 AH_TEMPLATE([CONFIG_RCU_COMPAT_ARCH], [Compatibility mode for i386 which lacks cmpxchg instruction.])
 AH_TEMPLATE([CONFIG_RCU_ARM_HAVE_DMB], [Use the dmb instruction if available for use on ARM.])
 AH_TEMPLATE([CONFIG_RCU_TLS], [TLS provided by the compiler.])
+AH_TEMPLATE([CONFIG_RCU_HAVE_CLOCK_GETTIME], [clock_gettime() is detected.])
 
 # Allow overriding storage used for TLS variables.
 AC_ARG_ENABLE([compiler-tls],
@@ -221,9 +222,9 @@ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
 ])
 
 # Search for clock_gettime
-AC_SEARCH_LIBS([clock_gettime], [rt], [],
-       [AC_MSG_ERROR([Cannot find clock_gettime function.])]
-)
+AC_SEARCH_LIBS([clock_gettime], [rt], [
+       AC_DEFINE([CONFIG_RCU_HAVE_CLOCK_GETTIME], [1])
+], [])
 
 # Check for pthread
 AC_CHECK_LIB([pthread], [pthread_create],

diff --git a/urcu/arch/generic.h b/urcu/arch/generic.h
index d42359557ef9147eafed2f2f077954e4246138ed..4b56ed7aaff00788a5fb4fbce712a146c5198a5d 100644 (file)
--- a/urcu/arch/generic.h
+++ b/urcu/arch/generic.h
@@ -153,6 +153,8 @@ extern "C" {
 #ifndef HAS_CAA_GET_CYCLES
 #define HAS_CAA_GET_CYCLES
 
+#ifdef CONFIG_RCU_HAVE_CLOCK_GETTIME
+
 #include <time.h>
 #include <stdint.h>
 
@@ -166,6 +168,38 @@ static inline caa_cycles_t caa_get_cycles (void)
                return -1ULL;
        return ((uint64_t) ts.tv_sec * 1000000000ULL) + ts.tv_nsec;
 }
+
+#elif defined(__APPLE__)
+
+#include <mach/mach.h>
+#include <mach/clock.h>
+#include <mach/mach_time.h>
+#include <time.h>
+#include <stdint.h>
+
+typedef uint64_t caa_cycles_t;
+
+static inline caa_cycles_t caa_get_cycles (void)
+{
+       mach_timespec_t ts = { 0, 0 };
+       static clock_serv_t clock_service;
+
+       if (caa_unlikely(!clock_service)) {
+               if (host_get_clock_service(mach_host_self(),
+                               SYSTEM_CLOCK, &clock_service))
+                       return -1ULL;
+       }
+       if (caa_unlikely(clock_get_time(clock_service, &ts)))
+               return -1ULL;
+       return ((uint64_t) ts.tv_sec * 1000000000ULL) + ts.tv_nsec;
+}
+
+#else
+
+#error caa_get_cycles() not implemented for this platform.
+
+#endif
+
 #endif /* HAS_CAA_GET_CYCLES */
 
 #ifdef __cplusplus

diff --git a/urcu/config.h.in b/urcu/config.h.in
index 98ea365d6040246eb0403da6a318a1ebb40fc2ff..4b856dcfc0900cd403ae59833b7f494d4c0f6a71 100644 (file)
--- a/urcu/config.h.in
+++ b/urcu/config.h.in
@@ -19,3 +19,6 @@
 
 /* TLS provided by the compiler. */
 #undef CONFIG_RCU_TLS
+
+/* clock_gettime() is detected. */
+#undef CONFIG_RCU_HAVE_CLOCK_GETTIME