Port changes from lttng-kt

[ust.git] / libust / tracerconst.h

diff --git a/libust/tracerconst.h b/libust/tracerconst.h
new file mode 100644 (file)
index 0000000..b23e743
--- /dev/null
+++ b/libust/tracerconst.h
@@ -0,0 +1,40 @@
+#ifndef TRACERCONST_H
+#define TRACERCONST_H
+
+/* Hardcoded event headers
+ *
+ * event header for a trace with active heartbeat : 27 bits timestamps
+ *
+ * headers are 32-bits aligned. In order to insure such alignment, a dynamic per
+ * trace alignment value must be done.
+ *
+ * Remember that the C compiler does align each member on the boundary
+ * equivalent to their own size.
+ *
+ * As relay subbuffers are aligned on pages, we are sure that they are 4 and 8
+ * bytes aligned, so the buffer header and trace header are aligned.
+ *
+ * Event headers are aligned depending on the trace alignment option.
+ *
+ * Note using C structure bitfields for cross-endianness and portability
+ * concerns.
+ */
+
+#define LTT_RESERVED_EVENTS    3
+#define LTT_EVENT_BITS         5
+#define LTT_FREE_EVENTS                ((1 << LTT_EVENT_BITS) - LTT_RESERVED_EVENTS)
+#define LTT_TSC_BITS           27
+#define LTT_TSC_MASK           ((1 << LTT_TSC_BITS) - 1)
+
+struct ltt_event_header {
+       u32 id_time;            /* 5 bits event id (MSB); 27 bits time (LSB) */
+};
+
+/* Reservation flags */
+#define        LTT_RFLAG_ID                    (1 << 0)
+#define        LTT_RFLAG_ID_SIZE               (1 << 1)
+#define        LTT_RFLAG_ID_SIZE_TSC           (1 << 2)
+
+#define LTT_MAX_SMALL_SIZE              0xFFFFU
+
+#endif /* TRACERCONST_H */