X-Git-Url: http://git.efficios.com/?p=babeltrace.git;a=blobdiff_plain;f=lib%2Ftrace-collection.c;h=9b60986f5018e98c54e870c471cf498d36d79839;hp=9bc5b1fcc8b0ecc543dd65b7a67734f4c44c8968;hb=9b3c1d6f8e01603488e317ffef7a8e3c15c98459;hpb=7f89ddce05f0a5c985d6333fbe70a992da4bd244

diff --git a/lib/trace-collection.c b/lib/trace-collection.c
index 9bc5b1fc..9b60986f 100644
--- a/lib/trace-collection.c
+++ b/lib/trace-collection.c
@@ -24,6 +24,7 @@
 #include <babeltrace/ctf-text/types.h>
 #include <babeltrace/trace-collection.h>
 #include <babeltrace/ctf-ir/metadata.h>	/* for clocks */
+#include <babeltrace/clock-internal.h>
 
 #include <inttypes.h>
 
@@ -38,24 +39,24 @@ static void check_clock_match(gpointer key, gpointer value, gpointer user_data)
 	struct clock_match *match = user_data;
 	struct ctf_clock *clock_a = value, *clock_b;
 
-	if (clock_a->uuid != 0) {
+	if (clock_a->absolute) {
 		/*
-		 * Lookup the the trace clocks into the collection
-		 * clocks.
+		 * Absolute time references, such as NTP, are looked up
+		 * by clock name.
 		 */
 		clock_b = g_hash_table_lookup(match->clocks,
-			(gpointer) (unsigned long) clock_a->uuid);
+			(gpointer) (unsigned long) clock_a->name);
 		if (clock_b) {
 			match->clock_match = clock_b;
 			return;
 		}
-	} else if (clock_a->absolute) {
+	} else if (clock_a->uuid != 0) {
 		/*
-		 * Absolute time references, such as NTP, are looked up
-		 * by clock name.
+		 * Lookup the the trace clocks into the collection
+		 * clocks.
 		 */
 		clock_b = g_hash_table_lookup(match->clocks,
-			(gpointer) (unsigned long) clock_a->name);
+			(gpointer) (unsigned long) clock_a->uuid);
 		if (clock_b) {
 			match->clock_match = clock_b;
 			return;
@@ -63,6 +64,19 @@ static void check_clock_match(gpointer key, gpointer value, gpointer user_data)
 	}
 }
 
+/*
+ * Note: if using a frequency different from 1GHz for clock->offset, it
+ * is recommended to express the seconds in offset_s, otherwise there
+ * will be a loss of precision caused by the limited size of the double
+ * mantissa.
+ */
+static
+uint64_t clock_offset_ns(struct ctf_clock *clock)
+{
+	return clock->offset_s * 1000000000ULL
+			+ clock_cycles_to_ns(clock, clock->offset);
+}
+
 static void clock_add(gpointer key, gpointer value, gpointer user_data)
 {
 	struct clock_match *clock_match = user_data;
@@ -81,15 +95,15 @@ static void clock_add(gpointer key, gpointer value, gpointer user_data)
 				(gpointer) (unsigned long) v);
 		if (!tc_clock) {
 			/*
-			 * For now, we only support CTF that has one
-			 * single clock uuid or name (absolute ref).
+			 * For now we only support CTF that has one
+			 * single clock uuid or name (absolute ref) per
+			 * trace.
 			 */
 			if (g_hash_table_size(tc_clocks) > 0) {
 				fprintf(stderr, "[error] Only CTF traces with a single clock description are supported by this babeltrace version.\n");
 			}
 			if (!clock_match->tc->offset_nr) {
-				clock_match->tc->offset_first =
-					(t_clock->offset_s * 1000000000ULL) + t_clock->offset;
+				clock_match->tc->offset_first = clock_offset_ns(t_clock);
 				clock_match->tc->delta_offset_first_sum = 0;
 				clock_match->tc->offset_nr++;
 				clock_match->tc->single_clock_offset_avg =
@@ -98,34 +112,32 @@ static void clock_add(gpointer key, gpointer value, gpointer user_data)
 			g_hash_table_insert(tc_clocks,
 				(gpointer) (unsigned long) v,
 				value);
-		} else {
+		} else if (!t_clock->absolute) {
 			int64_t diff_ns;
 
 			/*
-			 * Check that the offsets match. If not, warn
-			 * the user that we do an arbitrary choice.
+			 * For non-absolute clocks, check that the
+			 * offsets match. If not, warn the user that we
+			 * do an arbitrary choice.
 			 */
-			diff_ns = tc_clock->offset_s;
-			diff_ns -= t_clock->offset_s;
-			diff_ns *= 1000000000ULL;
-			diff_ns += tc_clock->offset;
-			diff_ns -= t_clock->offset;
+			diff_ns = clock_offset_ns(tc_clock) - clock_offset_ns(t_clock);
 			printf_debug("Clock \"%s\" offset between traces has a delta of %" PRIu64 " ns.",
 				g_quark_to_string(tc_clock->name),
 				diff_ns < 0 ? -diff_ns : diff_ns);
-			if (diff_ns > 10000) {
+			if (diff_ns > 10000 || diff_ns < -10000) {
 				fprintf(stderr, "[warning] Clock \"%s\" offset differs between traces (delta %" PRIu64 " ns). Using average.\n",
 					g_quark_to_string(tc_clock->name),
 					diff_ns < 0 ? -diff_ns : diff_ns);
 			}
 			/* Compute average */
 			clock_match->tc->delta_offset_first_sum +=
-				(t_clock->offset_s * 1000000000ULL) + t_clock->offset
-				- clock_match->tc->offset_first;
+				clock_offset_ns(t_clock) - clock_match->tc->offset_first;
 			clock_match->tc->offset_nr++;
 			clock_match->tc->single_clock_offset_avg =
 				clock_match->tc->offset_first
 				+ (clock_match->tc->delta_offset_first_sum / clock_match->tc->offset_nr);
+			/* Time need to use offset average */
+			clock_match->tc->clock_use_offset_avg = 1;
 		}
 	}
 }