trace/control.h

   1 /*
   2  * Interface for configuring and controlling the state of tracing events.
   3  *
   4  * Copyright (C) 2011-2016 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_vcpu_id:
  90  *
  91  * Get the per-vCPU identifier of an event.
  92  *
  93  * Special value #TRACE_VCPU_EVENT_COUNT means the event is not vCPU-specific
  94  * (does not have the "vcpu" property).
  95  */
  96 static TraceEventVCPUID trace_event_get_vcpu_id(TraceEvent *ev);
  97
  98 /**
  99  * trace_event_is_vcpu:
 100  *
 101  * Whether this is a per-vCPU event.
 102  */
 103 static bool trace_event_is_vcpu(TraceEvent *ev);
 104
 105 /**
 106  * trace_event_get_name:
 107  *
 108  * Get the name of an event.
 109  */
 110 static const char * trace_event_get_name(TraceEvent *ev);
 111
 112 /**
 113  * trace_event_get_state:
 114  * @id: Event identifier.
 115  *
 116  * Get the tracing state of an event (both static and dynamic).
 117  *
 118  * If the event has the disabled property, the check will have no performance
 119  * impact.
 120  *
 121  * As a down side, you must always use an immediate #TraceEventID value.
 122  */
 123 #define trace_event_get_state(id)                       \
 124     ((id ##_ENABLED) && trace_event_get_state_dynamic_by_id(id))
 125
 126 /**
 127  * trace_event_get_vcpu_state:
 128  * @vcpu: Target vCPU.
 129  * @id: Event identifier (TraceEventID).
 130  * @vcpu_id: Per-vCPU event identifier (TraceEventVCPUID).
 131  *
 132  * Get the tracing state of an event (both static and dynamic) for the given
 133  * vCPU.
 134  *
 135  * If the event has the disabled property, the check will have no performance
 136  * impact.
 137  *
 138  * As a down side, you must always use an immediate #TraceEventID value.
 139  */
 140 #define trace_event_get_vcpu_state(vcpu, id, vcpu_id)                   \
 141     ((id ##_ENABLED) && trace_event_get_vcpu_state_dynamic_by_vcpu_id(vcpu, vcpu_id))
 142
 143 /**
 144  * trace_event_get_state_static:
 145  * @id: Event identifier.
 146  *
 147  * Get the static tracing state of an event.
 148  *
 149  * Use the define 'TRACE_${EVENT_NAME}_ENABLED' for compile-time checks (it will
 150  * be set to 1 or 0 according to the presence of the disabled property).
 151  */
 152 static bool trace_event_get_state_static(TraceEvent *ev);
 153
 154 /**
 155  * trace_event_get_state_dynamic:
 156  *
 157  * Get the dynamic tracing state of an event.
 158  *
 159  * If the event has the 'vcpu' property, gets the OR'ed state of all vCPUs.
 160  */
 161 static bool trace_event_get_state_dynamic(TraceEvent *ev);
 162
 163 /**
 164  * trace_event_get_vcpu_state_dynamic:
 165  *
 166  * Get the dynamic tracing state of an event for the given vCPU.
 167  */
 168 static bool trace_event_get_vcpu_state_dynamic(CPUState *vcpu, TraceEvent *ev);
 169
 170 /**
 171  * trace_event_set_state:
 172  *
 173  * Set the tracing state of an event (only if possible).
 174  */
 175 #define trace_event_set_state(id, state)                \
 176     do {                                                \
 177         if ((id ##_ENABLED)) {                          \
 178             TraceEvent *_e = trace_event_id(id);        \
 179             trace_event_set_state_dynamic(_e, state);   \
 180         }                                               \
 181     } while (0)
 182
 183 /**
 184  * trace_event_set_vcpu_state:
 185  *
 186  * Set the tracing state of an event for the given vCPU (only if not disabled).
 187  */
 188 #define trace_event_set_vcpu_state(vcpu, id, state)                     \
 189     do {                                                                \
 190         if ((id ##_ENABLED)) {                                          \
 191             TraceEvent *_e = trace_event_id(id);                        \
 192             trace_event_set_vcpu_state_dynamic(vcpu, _e, state);        \
 193         }                                                               \
 194     } while (0)
 195
 196 /**
 197  * trace_event_set_state_dynamic:
 198  *
 199  * Set the dynamic tracing state of an event.
 200  *
 201  * If the event has the 'vcpu' property, sets the state on all vCPUs.
 202  *
 203  * Pre-condition: trace_event_get_state_static(ev) == true
 204  */
 205 void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
 206
 207 /**
 208  * trace_event_set_vcpu_state_dynamic:
 209  *
 210  * Set the dynamic tracing state of an event for the given vCPU.
 211  *
 212  * Pre-condition: trace_event_get_vcpu_state_static(ev) == true
 213  */
 214 void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
 215                                         TraceEvent *ev, bool state);
 216
 217
 218
 219 /**
 220  * trace_init_backends:
 221  * @file:   Name of trace output file; may be NULL.
 222  *          Corresponds to commandline option "-trace file=...".
 223  *
 224  * Initialize the tracing backend.
 225  *
 226  * Returns: Whether the backends could be successfully initialized.
 227  */
 228 bool trace_init_backends(void);
 229
 230 /**
 231  * trace_init_file:
 232  * @file:   Name of trace output file; may be NULL.
 233  *          Corresponds to commandline option "-trace file=...".
 234  *
 235  * Record the name of the output file for the tracing backend.
 236  * Exits if no selected backend does not support specifying the
 237  * output file, and a non-NULL file was passed.
 238  */
 239 void trace_init_file(const char *file);
 240
 241 /**
 242  * trace_init_vcpu:
 243  * @vcpu: Added vCPU.
 244  *
 245  * Set initial dynamic event state for a hot-plugged vCPU.
 246  */
 247 void trace_init_vcpu(CPUState *vcpu);
 248
 249 /**
 250  * trace_list_events:
 251  *
 252  * List all available events.
 253  */
 254 void trace_list_events(void);
 255
 256 /**
 257  * trace_enable_events:
 258  * @line_buf: A string with a glob pattern of events to be enabled or,
 259  *            if the string starts with '-', disabled.
 260  *
 261  * Enable or disable matching events.
 262  */
 263 void trace_enable_events(const char *line_buf);
 264
 265 /**
 266  * Definition of QEMU options describing trace subsystem configuration
 267  */
 268 extern QemuOptsList qemu_trace_opts;
 269
 270 /**
 271  * trace_opt_parse:
 272  * @optarg: A string argument of --trace command line argument
 273  *
 274  * Initialize tracing subsystem.
 275  *
 276  * Returns the filename to save trace to.  It must be freed with g_free().
 277  */
 278 char *trace_opt_parse(const char *optarg);
 279
 280
 281 #include "trace/control-internal.h"
 282
 283 #endif /* TRACE__CONTROL_H */