ltt/branches/poly/include/ltt/ltt.h

   1 #ifndef LTT_H
   2 #define LTT_H
   3
   4 #include <ltt/time.h>
   5 #include <glib.h>
   6
   7 /* A trace is associated with a tracing session run on a single, possibly
   8    multi-cpu, system. It is defined as a pathname to a directory containing
   9    all the relevant trace files. All the tracefiles for a trace were
  10    generated in a single system for the same time period by the same
  11    trace daemon. They simply contain different events. Typically control
  12    tracefiles contain the important events (process creations and registering
  13    tracing facilities) for all CPUs, and one file for each CPU contains all
  14    the events for that CPU. All the tracefiles within the same trace directory
  15    then use the exact same id numbers for event types.
  16
  17    A tracefile (LttTracefile) contains a list of events (LttEvent) sorted
  18    by time for each CPU; events from different CPUs may be slightly out of
  19    order, especially using the (possibly drifting) cycle counters as
  20    time unit.
  21
  22    A facility is a list of event types (LttEventType), declared in a special
  23    eventdefs file. A corresponding checksum differentiates different
  24    facilities which would have the same name but a different content
  25    (e.g., different versions). The files are stored within the trace
  26    directory and are accessed automatically upon opening a trace.
  27    The list of facilities (and associated checksum) used in a trace
  28    must be known in order to properly decode the contained events. An event
  29    is stored in the "facilities" control tracefile to denote each different
  30    facility used.
  31
  32    Event types (LttEventType) refer to data types (LttType) describing
  33    their content. The data types supported are integer and unsigned integer
  34    (of various length), enumerations (a special form of unsigned integer),
  35    floating point (of various length), fixed size arrays, sequence
  36    (variable sized arrays), structures and null terminated strings.
  37    The elements of arrays and sequences, and the data members for
  38    structures, may be of any nested data type (LttType).
  39
  40    An LttField is a special object to denote a specific, possibly nested,
  41    field within an event type. Suppose an event type socket_connect is a
  42    structure containing two data members, source and destination, of type
  43    socket_address. Type socket_address contains two unsigned integer
  44    data members, ip and port. An LttField is different from a data type
  45    structure member since it can denote a specific nested field, like the
  46    source port, and store associated access information (byte offset within
  47    the event data). The LttField objects are trace specific since the
  48    contained information (byte offsets) may vary with the architecture
  49    associated to the trace. */
  50
  51 typedef struct _LttTrace LttTrace;
  52
  53 typedef struct _LttTracefile LttTracefile;
  54
  55 typedef struct _LttFacility LttFacility;
  56
  57 typedef struct _LttEventType LttEventType;
  58
  59 typedef struct _LttType LttType;
  60
  61 typedef struct _LttField LttField;
  62
  63 typedef struct _LttEvent LttEvent;
  64
  65 typedef struct _LttSystemDescription LttSystemDescription;
  66
  67 /* Checksums are used to differentiate facilities which have the same name
  68    but differ. */
  69
  70 typedef unsigned long LttChecksum;
  71
  72
  73 /* Events are usually stored with the easily obtained CPU clock cycle count,
  74    ltt_cycle_count. This can be converted to the real time value, LttTime,
  75    using linear interpolation between regularly sampled values (e.g. a few
  76    times per second) of the real time clock with their corresponding
  77    cycle count values. */
  78
  79
  80 typedef struct _TimeInterval{
  81   LttTime startTime;
  82   LttTime endTime;
  83 } TimeInterval;
  84
  85
  86 typedef guint64 LttCycleCount;
  87
  88
  89 /* Event positions are used to seek within a tracefile based on
  90    the block number and event position within the block. */
  91
  92 typedef struct _LttEventPosition LttEventPosition;
  93
  94
  95 /* Differences between architectures include word sizes, endianess,
  96    alignment, floating point format and calling conventions. For a
  97    packed binary trace, endianess and size matter, assuming that the
  98    floating point format is standard (and is seldom used anyway). */
  99
 100 typedef enum _LttArchSize
 101 { LTT_LP32, LTT_ILP32, LTT_LP64, LTT_ILP64, LTT_UNKNOWN
 102 } LttArchSize;
 103
 104
 105 typedef enum _LttArchEndian
 106 { LTT_LITTLE_ENDIAN, LTT_BIG_ENDIAN
 107 } LttArchEndian;
 108
 109 typedef enum _LttTypeEnum
 110 { LTT_INT, LTT_UINT, LTT_FLOAT, LTT_STRING, LTT_ENUM, LTT_ARRAY,
 111   LTT_SEQUENCE, LTT_STRUCT, LTT_UNION
 112 } LttTypeEnum;
 113
 114
 115 #endif // LTT_H