| 1 | #ifndef LTT_H |
| 2 | #define LTT_H |
| 3 | |
| 4 | |
| 5 | /* A trace is associated with a tracing session run on a single, possibly |
| 6 | multi-cpu, system. It is defined as a pathname to a directory containing |
| 7 | all the relevant trace files. All the tracefiles for a trace were |
| 8 | generated in a single system for the same time period by the same |
| 9 | trace daemon. They simply contain different events. Typically one file |
| 10 | contains the important events (process creations and registering tracing |
| 11 | facilities) for all CPUs, and one file for each CPU contains all the |
| 12 | events for that CPU. All the tracefiles within the same trace directory |
| 13 | then use the exact same id numbers for event types. |
| 14 | |
| 15 | A tracefile (ltt_tracefile) contains a list of events (ltt_event) sorted |
| 16 | by time for each CPU; events from different CPUs may be slightly out of |
| 17 | order, especially using the (possibly drifting) cycle counters as |
| 18 | time unit. |
| 19 | |
| 20 | A facility is a list of event types (ltt_eventtype), declared in a special |
| 21 | .event file. An associated checksum differentiates different facilities |
| 22 | which would have the same name but a different content (e.g., different |
| 23 | versions). |
| 24 | |
| 25 | The list of facilities (and associated checksum) used in a tracefile |
| 26 | must be known in order to properly decode the contained events. An event |
| 27 | is usually stored in the trace to denote each different "facility used". |
| 28 | While many facilities may be present when the trace starts, new |
| 29 | facilities may be introduced later as kernel modules are loaded. |
| 30 | This is fine as long as the "facility used" event precedes any event |
| 31 | described in that facility. |
| 32 | |
| 33 | Event types (ltt_eventtype) refer to data types (ltt_type) describing |
| 34 | their content. The data types supported are integer and unsigned integer |
| 35 | (of various length), enumerations (a special form of unsigned integer), |
| 36 | floating point (of various length), fixed size arrays, sequence |
| 37 | (variable sized arrays), structures and null terminated strings. |
| 38 | The elements of arrays and sequences, and the data members for |
| 39 | structures, may be of any nested data type (ltt_type). |
| 40 | |
| 41 | An ltt_field is a special object to denote a specific, possibly nested, |
| 42 | field within an event type. Suppose an event type socket_connect is a |
| 43 | structure containing two data membes, source and destination, of type |
| 44 | socket_address. Type socket_address contains two unsigned integer |
| 45 | data members, ip and port. An ltt_field is different from a data type |
| 46 | structure member since it can denote a specific nested field, like the |
| 47 | source port, and store associated access information (byte offset within |
| 48 | the event data). The ltt_field objects are tracefile specific since the |
| 49 | contained information (byte offsets) may vary with the architecture |
| 50 | associated to the tracefile. */ |
| 51 | |
| 52 | typedef struct _ltt_tracefile ltt_tracefile; |
| 53 | |
| 54 | typedef struct _ltt_facility ltt_facility; |
| 55 | |
| 56 | typedef struct _ltt_eventtype ltt_eventtype; |
| 57 | |
| 58 | typedef struct _ltt_type ltt_type; |
| 59 | |
| 60 | typedef struct _ltt_field ltt_field; |
| 61 | |
| 62 | typedef struct _ltt_event ltt_event; |
| 63 | |
| 64 | |
| 65 | /* Different types allowed */ |
| 66 | |
| 67 | typedef enum _ltt_type_enum |
| 68 | { LTT_INT, LTT_UINT, LTT_FLOAT, LTT_STRING, LTT_ENUM, LTT_ARRAY, |
| 69 | LTT_SEQUENCE, LTT_STRUCT |
| 70 | } ltt_type_enum; |
| 71 | |
| 72 | |
| 73 | /* Checksums are used to differentiate facilities which have the same name |
| 74 | but differ. */ |
| 75 | |
| 76 | typedef unsigned long ltt_checksum; |
| 77 | |
| 78 | |
| 79 | /* Events are usually stored with the easily obtained CPU clock cycle count, |
| 80 | ltt_cycle_count. This can be converted to the real time value, ltt_time, |
| 81 | using linear interpolation between regularly sampled values (e.g. a few |
| 82 | times per second) of the real time clock with their corresponding |
| 83 | cycle count values. */ |
| 84 | |
| 85 | typedef struct timespec ltt_time; |
| 86 | |
| 87 | typedef uint64_t ltt_cycle_count; |
| 88 | |
| 89 | typedef enum _ltt_arch_size |
| 90 | { LTT_LP32, LTT_ILP32, LTT_LP64, LTT_ILP64, LTT_UNKNOWN |
| 91 | } ltt_arch_size; |
| 92 | |
| 93 | typedef enum _ltt_arch_endian |
| 94 | { LTT_LITTLE_ENDIAN, LTT_BIG_ENDIAN |
| 95 | } ltt_arch_endian; |
| 96 | |
| 97 | |
| 98 | |
| 99 | #include <ltt/ltt-private.h> |
| 100 | |
| 101 | |
| 102 | #endif // LTT_H |