X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=liblttng-ust%2Fclock.h;h=a7e8eb7b49e062b1e5ebe9f24cd7d60278a4c64e;hb=c7667bfebfa1d054ad8d54fd98ada3c86184e327;hp=88eca432a5733f7e4bc35f1878b911617a5119d5;hpb=277d6e1d016e69184fd49b867ff1268d3ff668f5;p=lttng-ust.git

diff --git a/liblttng-ust/clock.h b/liblttng-ust/clock.h
index 88eca432..a7e8eb7b 100644
--- a/liblttng-ust/clock.h
+++ b/liblttng-ust/clock.h
@@ -25,34 +25,46 @@
 #include <stdint.h>
 #include <stddef.h>
 #include <stdio.h>
+#include <urcu/system.h>
+#include <urcu/arch.h>
+#include <lttng/ust-clock.h>
+
 #include "lttng-ust-uuid.h"
 
-/* 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);
+};
 
-/*
- * Currently using the kernel MONOTONIC clock, waiting for kernel-side
- * LTTng to implement mmap'd trace clock.
- */
+extern struct lttng_trace_clock *lttng_trace_clock;
+
+void lttng_ust_clock_init(void);
 
-/* Choosing correct trace clock */
+/* Use the kernel MONOTONIC clock. */
 
 static __inline__
-uint64_t trace_clock_read64(void)
+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__
-uint64_t trace_clock_freq(void)
+uint64_t trace_clock_freq_monotonic(void)
 {
 	return 1000000000ULL;
 }
 
 static __inline__
-int trace_clock_uuid(char *uuid)
+int trace_clock_uuid_monotonic(char *uuid)
 {
 	int ret = 0;
 	size_t len;
@@ -78,4 +90,82 @@ end:
 	return ret;
 }
 
+static __inline__
+const char *trace_clock_name_monotonic(void)
+{
+	return "monotonic";
+}
+
+static __inline__
+const char *trace_clock_description_monotonic(void)
+{
+	return "Monotonic Clock";
+}
+
+static __inline__
+uint64_t trace_clock_read64(void)
+{
+	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();
+	}
+}
+
+static __inline__
+uint64_t trace_clock_freq(void)
+{
+	struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
+
+	if (!ltc) {
+		return trace_clock_freq_monotonic();
+	} else {
+		cmm_read_barrier_depends();	/* load ltc before content */
+		return ltc->freq();
+	}
+}
+
+static __inline__
+int trace_clock_uuid(char *uuid)
+{
+	struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
+
+	cmm_read_barrier_depends();	/* load ltc before content */
+	/* Use default UUID cb when NULL */
+	if (!ltc || !ltc->uuid) {
+		return trace_clock_uuid_monotonic(uuid);
+	} else {
+		return ltc->uuid(uuid);
+	}
+}
+
+static __inline__
+const char *trace_clock_name(void)
+{
+	struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
+
+	if (!ltc) {
+		return trace_clock_name_monotonic();
+	} else {
+		cmm_read_barrier_depends();	/* load ltc before content */
+		return ltc->name();
+	}
+}
+
+static __inline__
+const char *trace_clock_description(void)
+{
+	struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
+
+	if (!ltc) {
+		return trace_clock_description_monotonic();
+	} else {
+		cmm_read_barrier_depends();	/* load ltc before content */
+		return ltc->description();
+	}
+}
+
 #endif /* _UST_CLOCK_H */