libust/tracerconst.h

   1 #ifndef TRACERCONST_H
   2 #define TRACERCONST_H
   3
   4 /* Hardcoded event headers
   5  *
   6  * event header for a trace with active heartbeat : 27 bits timestamps
   7  *
   8  * headers are 32-bits aligned. In order to insure such alignment, a dynamic per
   9  * trace alignment value must be done.
  10  *
  11  * Remember that the C compiler does align each member on the boundary
  12  * equivalent to their own size.
  13  *
  14  * As relay subbuffers are aligned on pages, we are sure that they are 4 and 8
  15  * bytes aligned, so the buffer header and trace header are aligned.
  16  *
  17  * Event headers are aligned depending on the trace alignment option.
  18  *
  19  * Note using C structure bitfields for cross-endianness and portability
  20  * concerns.
  21  */
  22
  23 #define LTT_RESERVED_EVENTS     3
  24 #define LTT_EVENT_BITS          5
  25 #define LTT_FREE_EVENTS         ((1 << LTT_EVENT_BITS) - LTT_RESERVED_EVENTS)
  26 #define LTT_TSC_BITS            27
  27 #define LTT_TSC_MASK            ((1 << LTT_TSC_BITS) - 1)
  28
  29 struct ltt_event_header {
  30         u32 id_time;            /* 5 bits event id (MSB); 27 bits time (LSB) */
  31 };
  32
  33 /* Reservation flags */
  34 #define LTT_RFLAG_ID                    (1 << 0)
  35 #define LTT_RFLAG_ID_SIZE               (1 << 1)
  36 #define LTT_RFLAG_ID_SIZE_TSC           (1 << 2)
  37
  38 #define LTT_MAX_SMALL_SIZE              0xFFFFU
  39
  40 #endif /* TRACERCONST_H */