Move the clock plugin implementation to liblttng-ust-common

[lttng-ust.git] / src / common / clock.h

diff --git a/src/common/clock.h b/src/common/clock.h
index a0bf24991c2e43654463ddfb4b41244a04dbb7c0..e9407f2608cd154ee3c602411868bedcc90b91e3 100644 (file)
--- a/src/common/clock.h
+++ b/src/common/clock.h
@@ -7,9 +7,56 @@
 #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 */