trace/control.h

   1 /*
   2  * Interface for configuring and controlling the state of tracing events.
   3  *
   4  * Copyright (C) 2011-2014 Lluís Vilanova <vilanova@ac.upc.edu>
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  */
   9
  10 #ifndef TRACE__CONTROL_H
  11 #define TRACE__CONTROL_H
  12
  13 #include "qemu-common.h"
  14 #include "trace/generated-events.h"
  15
  16
  17 /**
  18  * TraceEventID:
  19  *
  20  * Unique tracing event identifier.
  21  *
  22  * These are named as 'TRACE_${EVENT_NAME}'.
  23  *
  24  * See also: "trace/generated-events.h"
  25  */
  26 enum TraceEventID;
  27
  28 /**
  29  * trace_event_id:
  30  * @id: Event identifier.
  31  *
  32  * Get an event by its identifier.
  33  *
  34  * This routine has a constant cost, as opposed to trace_event_name and
  35  * trace_event_pattern.
  36  *
  37  * Pre-conditions: The identifier is valid.
  38  *
  39  * Returns: pointer to #TraceEvent.
  40  *
  41  */
  42 static TraceEvent *trace_event_id(TraceEventID id);
  43
  44 /**
  45  * trace_event_name:
  46  * @id: Event name.
  47  *
  48  * Search an event by its name.
  49  *
  50  * Returns: pointer to #TraceEvent or NULL if not found.
  51  */
  52 TraceEvent *trace_event_name(const char *name);
  53
  54 /**
  55  * trace_event_pattern:
  56  * @pat: Event name pattern.
  57  * @ev: Event to start searching from (not included).
  58  *
  59  * Get all events with a given name pattern.
  60  *
  61  * Returns: pointer to #TraceEvent or NULL if not found.
  62  */
  63 TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev);
  64
  65 /**
  66  * trace_event_is_pattern:
  67  *
  68  * Whether the given string is an event name pattern.
  69  */
  70 static bool trace_event_is_pattern(const char *str);
  71
  72 /**
  73  * trace_event_count:
  74  *
  75  * Return the number of events.
  76  */
  77 static TraceEventID trace_event_count(void);
  78
  79
  80
  81 /**
  82  * trace_event_get_id:
  83  *
  84  * Get the identifier of an event.
  85  */
  86 static TraceEventID trace_event_get_id(TraceEvent *ev);
  87
  88 /**
  89  * trace_event_get_name:
  90  *
  91  * Get the name of an event.
  92  */
  93 static const char * trace_event_get_name(TraceEvent *ev);
  94
  95 /**
  96  * trace_event_get_state:
  97  * @id: Event identifier.
  98  *
  99  * Get the tracing state of an event (both static and dynamic).
 100  *
 101  * If the event has the disabled property, the check will have no performance
 102  * impact.
 103  *
 104  * As a down side, you must always use an immediate #TraceEventID value.
 105  */
 106 #define trace_event_get_state(id)                       \
 107     ((id ##_ENABLED) && trace_event_get_state_dynamic(trace_event_id(id)))
 108
 109 /**
 110  * trace_event_get_state_static:
 111  * @id: Event identifier.
 112  *
 113  * Get the static tracing state of an event.
 114  *
 115  * Use the define 'TRACE_${EVENT_NAME}_ENABLED' for compile-time checks (it will
 116  * be set to 1 or 0 according to the presence of the disabled property).
 117  */
 118 static bool trace_event_get_state_static(TraceEvent *ev);
 119
 120 /**
 121  * trace_event_get_state_dynamic:
 122  *
 123  * Get the dynamic tracing state of an event.
 124  */
 125 static bool trace_event_get_state_dynamic(TraceEvent *ev);
 126
 127 /**
 128  * trace_event_set_state:
 129  *
 130  * Set the tracing state of an event (only if possible).
 131  */
 132 #define trace_event_set_state(id, state)                \
 133     do {                                                \
 134         if ((id ##_ENABLED)) {                          \
 135             TraceEvent *_e = trace_event_id(id);        \
 136             trace_event_set_state_dynamic(_e, state);   \
 137         }                                               \
 138     } while (0)
 139
 140 /**
 141  * trace_event_set_state_dynamic:
 142  *
 143  * Set the dynamic tracing state of an event.
 144  *
 145  * Pre-condition: trace_event_get_state_static(ev) == true
 146  */
 147 static void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
 148
 149
 150
 151 /**
 152  * trace_init_backends:
 153  * @events: Name of file with events to be enabled at startup; may be NULL.
 154  *          Corresponds to commandline option "-trace events=...".
 155  * @file:   Name of trace output file; may be NULL.
 156  *          Corresponds to commandline option "-trace file=...".
 157  *
 158  * Initialize the tracing backend.
 159  *
 160  * Returns: Whether the backends could be successfully initialized.
 161  */
 162 bool trace_init_backends(const char *events, const char *file);
 163
 164
 165 #include "trace/control-internal.h"
 166
 167 #endif  /* TRACE__CONTROL_H */