X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Fclock.h;h=d5548e90e4fe9a301f06fd6dc86ad400c80ff091;hb=41d1e173b52e80030b05ce7f25a45ae59765e40e;hp=23294d2b8c2fdf771d043e775b83664ab3d19549;hpb=dc190cc1f8ddccfa7b0b8323ed157afb29a0ebb7;p=lttng-ust.git

diff --git a/liblttng-ust/clock.h b/liblttng-ust/clock.h
index 23294d2b..d5548e90 100644
--- a/liblttng-ust/clock.h
+++ b/liblttng-ust/clock.h
@@ -24,27 +24,50 @@
 #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>
 
-/* TRACE CLOCK */
+#include "lttng-ust-uuid.h"
 
-/*
- * Currently using the kernel MONOTONIC clock, waiting for kernel-side
- * LTTng to implement mmap'd trace clock.
- */
+struct lttng_trace_clock {
+	uint64_t (*read64)(void);
+	uint64_t (*freq)(void);
+	int (*uuid)(char *uuid);
+	const char *(*name)(void);
+	const char *(*description)(void);
+};
+
+extern struct lttng_trace_clock *lttng_trace_clock;
 
-/* Choosing correct trace clock */
+void lttng_ust_clock_init(void);
 
-static __inline__ uint64_t trace_clock_read64(void)
+/* Use the kernel MONOTONIC clock. */
+
+static __inline__
+uint64_t trace_clock_read64_monotonic(void)
 {
 	struct timespec ts;
 
-	clock_gettime(CLOCK_MONOTONIC, &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__ uint32_t trace_clock_freq_scale(void)
+static __inline__
+uint64_t trace_clock_read64(void)
 {
-	return 1;
+	struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_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_CLOCK_H */