X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=ltt-ring-buffer-client.h;h=904c42eb466b68e8745f1108ad50922460ba4980;hb=b265a505ba25418104f3425e4475f45419844e8a;hp=30f0104fdc46728468f78ddb3c33b977178a87de;hpb=da4e23320ee3bed6a19fe29c8a0b8b78387be7f3;p=lttng-modules.git diff --git a/ltt-ring-buffer-client.h b/ltt-ring-buffer-client.h index 30f0104f..904c42eb 100644 --- a/ltt-ring-buffer-client.h +++ b/ltt-ring-buffer-client.h @@ -22,6 +22,14 @@ * you ever add/remove a field from this header. Packed attribute is not used * because gcc generates poor code on at least powerpc and mips. Don't ever * let gcc add padding between the structure elements. + * + * The guarantee we have with timestamps is that all the events in a + * packet are included (inclusive) within the begin/end timestamps of + * the packet. Another guarantee we have is that the "timestamp begin", + * as well as the event timestamps, are monotonically increasing (never + * decrease) when moving forward in a stream (physically). But this + * guarantee does not apply to "timestamp end", because it is sampled at + * commit time, which is not ordered with respect to space reservation. */ struct packet_header {