#ifndef _UST_COMMON_CLOCK_H
#define _UST_COMMON_CLOCK_H
+#include <time.h>
+#include <sys/time.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <stdio.h>
+
+#include <urcu/system.h>
+#include <urcu/arch.h>
+#include <lttng/ust-clock.h>
+
+struct lttng_ust_trace_clock {
+ uint64_t (*read64)(void);
+ uint64_t (*freq)(void);
+ int (*uuid)(char *uuid);
+ const char *(*name)(void);
+ const char *(*description)(void);
+};
+
/*
- * Part of the private ABI between liblttng-ust and liblttng-ust-ctl.
+ * The trace clock is a public symbol of liblttng-ust-common accessed by other
+ * libraries through the trace_clock_read64 static inline function. It is
+ * initialised in the liblttng-ust-common constructor.
*/
-void lttng_ust_clock_init(void);
+extern struct lttng_ust_trace_clock *lttng_ust_trace_clock;
+
+/* Use the kernel MONOTONIC clock. */
+
+static __inline__
+uint64_t trace_clock_read64_monotonic(void)
+{
+ struct timespec ts;
+
+ if (caa_unlikely(clock_gettime(CLOCK_MONOTONIC, &ts))) {
+ ts.tv_sec = 0;
+ ts.tv_nsec = 0;
+ }
+ return ((uint64_t) ts.tv_sec * 1000000000ULL) + ts.tv_nsec;
+}
+
+static __inline__
+uint64_t trace_clock_read64(void)
+{
+ struct lttng_ust_trace_clock *ltc = CMM_LOAD_SHARED(lttng_ust_trace_clock);
+
+ if (caa_likely(!ltc)) {
+ return trace_clock_read64_monotonic();
+ } else {
+ cmm_read_barrier_depends(); /* load ltc before content */
+ return ltc->read64();
+ }
+}
#endif /* _UST_COMMON_CLOCK_H */