Add clock absolute field

[ctf.git] / common-trace-format-specification.txt

diff --git a/common-trace-format-specification.txt b/common-trace-format-specification.txt
index 528029dc9d4ce799f394cf5105e159d1201869ac..c52beb9ddd42a8210b342f7f1acb889f7a3aa416 100644 (file)
--- a/common-trace-format-specification.txt
+++ b/common-trace-format-specification.txt
@@ -1257,14 +1257,19 @@ the clock and clock topology should be described in a "clock"
 description block, e.g.:
 
 clock {
-       name = cycle_counter;
+       name = cycle_counter_sync;
        uuid = "62189bee-96dc-11e0-91a8-cfa3d89f3923";
-       description = "Local CPU cycle counter";
+       description = "Cycle counter synchronized across CPUs";
        freq = 1000000000;             /* frequency, in Hz */
        /* precision in seconds is: 1000 * (1/freq) */
        precision = 1000;
-       /* clock value offset from Epoch is: offset * (1/freq) */
-       offset = 1326476837897235420;
+       /*
+        * clock value offset from Epoch is:
+        * offset_s + (offset * (1/freq))
+        */
+       offset_s = 1326476837;
+       offset = 897235420;
+       absolute = FALSE;
 };
 
 The mandatory "name" field specifies the name of the clock identifier,
@@ -1275,17 +1280,23 @@ can be added with the "description" field. The "freq" field is the
 initial frequency of the clock, in Hz. If the "freq" field is not
 present, the frequency is assumed to be 1000000000 (providing clock
 increment of 1 ns). The optional "precision" field details the
-uncertainty on the clock measurements, in (1/freq) units. The "offset"
-field indicates the offset from POSIX.1 Epoch, 1970-01-01 00:00:00 +0000
-(UTC), to the zero of value of the clock, in (1/freq) units. If the
-"offset" field is not present, it is assigned the 0 value.
+uncertainty on the clock measurements, in (1/freq) units. The "offset_s"
+and "offset" fields indicate the offset from POSIX.1 Epoch, 1970-01-01
+00:00:00 +0000 (UTC), to the zero of value of the clock. The "offset_s"
+field is in seconds. The "offset" field is in (1/freq) units. If any of
+the "offset_s" or "offset" field is not present, it is assigned the 0
+value. The field "absolute" is TRUE if the clock is a global reference
+across different clock uuid (e.g. NTP time). Otherwise, "absolute" is
+FALSE, and the clock can be considered as synchronized only with other
+clocks that have the same uuid.
+
 
 Secondly, a reference to this clock should be added within an integer
 type:
 
 typealias integer {
        size = 64; align = 1; signed = false;
-       map = clock.cycle_counter.value;
+       map = clock.cycle_counter_sync.value;
 } := uint64_ccnt_t;
 
 Thirdly, stream declarations can reference the clock they use as a