X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Fltt-events.c;h=85afc1ba63599027ea930d4aea52a0f07856241c;hb=939950af98d044a3b0632cad5293f91cb1493ef8;hp=ee88b43142d6e39c57f974102ba45328a7aef210;hpb=31c12beac8ce45308a787227d1d03217523ac219;p=lttng-ust.git

diff --git a/liblttng-ust/ltt-events.c b/liblttng-ust/ltt-events.c
index ee88b431..85afc1ba 100644
--- a/liblttng-ust/ltt-events.c
+++ b/liblttng-ust/ltt-events.c
@@ -20,6 +20,9 @@
 #include <sys/ipc.h>
 #include <stdint.h>
 #include <stddef.h>
+#include <inttypes.h>
+#include <time.h>
+#include "clock.h"
 
 #include <urcu-bp.h>
 #include <urcu/compiler.h>
@@ -309,20 +312,10 @@ int ltt_session_enable(struct ltt_session *session)
 	cds_list_for_each_entry(chan, &session->chan, list) {
 		if (chan->header_type)
 			continue;		/* don't change it if session stop/restart */
-		/*
-		 * Because we don't use any timer in the application, we
-		 * currently cannot guarantee that we have frequent
-		 * events that let us detect 27-bit overflows.
-		 * Therefore, for now, we force large event headers,
-		 * which contain 64-bit timestamps.
-		 */
-		chan->header_type = 2;  /* large */
-#if 0
 		if (chan->free_event_id < 31)
 			chan->header_type = 1;	/* compact */
 		else
 			chan->header_type = 2;	/* large */
-#endif //0
 	}
 
 	CMM_ACCESS_ONCE(session->active) = 1;
@@ -997,8 +990,8 @@ int _ltt_stream_packet_context_declare(struct ltt_session *session)
 {
 	return lttng_metadata_printf(session,
 		"struct packet_context {\n"
-		"	uint64_t timestamp_begin;\n"
-		"	uint64_t timestamp_end;\n"
+		"	uint64_clock_monotonic_t timestamp_begin;\n"
+		"	uint64_clock_monotonic_t timestamp_end;\n"
 		"	uint32_t events_discarded;\n"
 		"	uint32_t content_size;\n"
 		"	uint32_t packet_size;\n"
@@ -1024,11 +1017,11 @@ int _ltt_event_header_declare(struct ltt_session *session)
 	"	enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
 	"	variant <id> {\n"
 	"		struct {\n"
-	"			uint27_t timestamp;\n"
+	"			uint27_clock_monotonic_t timestamp;\n"
 	"		} compact;\n"
 	"		struct {\n"
 	"			uint32_t id;\n"
-	"			uint64_t timestamp;\n"
+	"			uint64_clock_monotonic_t timestamp;\n"
 	"		} extended;\n"
 	"	} v;\n"
 	"} align(%u);\n"
@@ -1037,11 +1030,11 @@ int _ltt_event_header_declare(struct ltt_session *session)
 	"	enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
 	"	variant <id> {\n"
 	"		struct {\n"
-	"			uint32_t timestamp;\n"
+	"			uint32_clock_monotonic_t timestamp;\n"
 	"		} compact;\n"
 	"		struct {\n"
 	"			uint32_t id;\n"
-	"			uint64_t timestamp;\n"
+	"			uint64_clock_monotonic_t timestamp;\n"
 	"		} extended;\n"
 	"	} v;\n"
 	"} align(%u);\n\n",
@@ -1050,6 +1043,31 @@ int _ltt_event_header_declare(struct ltt_session *session)
 	);
 }
 
+/*
+ * Approximation of NTP time of day to clock monotonic correlation,
+ * taken at start of trace.
+ * Yes, this is only an approximation. Yes, we can (and will) do better
+ * in future versions.
+ */
+static
+uint64_t measure_clock_offset(void)
+{
+	uint64_t offset, monotonic[2], realtime;
+	struct timespec rts = { 0, 0 };
+	int ret;
+
+	monotonic[0] = trace_clock_read64();
+	ret = clock_gettime(CLOCK_REALTIME, &rts);	
+	if (ret < 0)
+		return 0;
+	monotonic[1] = trace_clock_read64();
+	offset = (monotonic[0] + monotonic[1]) >> 1;
+	realtime = rts.tv_sec * 1000000000ULL;
+	realtime += rts.tv_nsec;
+	offset = realtime - offset;
+	return offset;
+}
+
 /*
  * Output metadata into this session's metadata buffers.
  */
@@ -1057,7 +1075,7 @@ static
 int _ltt_session_metadata_statedump(struct ltt_session *session)
 {
 	unsigned char *uuid_c = session->uuid;
-	char uuid_s[37];
+	char uuid_s[37], clock_uuid_s[CLOCK_UUID_LEN];
 	struct ltt_channel *chan;
 	struct ltt_event *event;
 	int ret = 0;
@@ -1113,6 +1131,56 @@ int _ltt_session_metadata_statedump(struct ltt_session *session)
 	if (ret)
 		goto end;
 
+	ret = lttng_metadata_printf(session,
+		"clock {\n"
+		"	name = %s;\n",
+		"monotonic"
+		);
+	if (ret)
+		goto end;
+
+	if (!trace_clock_uuid(clock_uuid_s)) {
+		ret = lttng_metadata_printf(session,
+			"	uuid = \"%s\";\n",
+			clock_uuid_s
+			);
+		if (ret)
+			goto end;
+	}
+
+	ret = lttng_metadata_printf(session,
+		"	description = \"Monotonic Clock\";\n"
+		"	freq = %" PRIu64 "; /* Frequency, in Hz */\n"
+		"	/* clock value offset from Epoch is: offset * (1/freq) */\n"
+		"	offset = %" PRIu64 ";\n"
+		"};\n\n",
+		trace_clock_freq(),
+		measure_clock_offset()
+		);
+	if (ret)
+		goto end;
+
+	ret = lttng_metadata_printf(session,
+		"typealias integer {\n"
+		"	size = 27; align = 1; signed = false;\n"
+		"	map = clock.monotonic.value;\n"
+		"} := uint27_clock_monotonic_t;\n"
+		"\n"
+		"typealias integer {\n"
+		"	size = 32; align = %u; signed = false;\n"
+		"	map = clock.monotonic.value;\n"
+		"} := uint32_clock_monotonic_t;\n"
+		"\n"
+		"typealias integer {\n"
+		"	size = 64; align = %u; signed = false;\n"
+		"	map = clock.monotonic.value;\n"
+		"} := uint64_clock_monotonic_t;\n\n",
+		lttng_alignof(uint32_t) * CHAR_BIT,
+		lttng_alignof(uint64_t) * CHAR_BIT
+		);
+	if (ret)
+		goto end;
+
 	ret = _ltt_stream_packet_context_declare(session);
 	if (ret)
 		goto end;