5b808275f3
Adds support to compile QEMU with multiple tracing backends at the same time. For example, you can compile QEMU with: $ ./configure --enable-trace-backends=ftrace,dtrace Where 'ftrace' can be handy for having an in-flight record of events, and 'dtrace' can be later used to extract more information from the system. This patch allows having both available without recompiling QEMU. Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
175 lines
4.1 KiB
C
175 lines
4.1 KiB
C
/*
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* Interface for configuring and controlling the state of tracing events.
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*
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* Copyright (C) 2011-2014 Lluís Vilanova <vilanova@ac.upc.edu>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#ifndef TRACE__CONTROL_H
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#define TRACE__CONTROL_H
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#include "qemu-common.h"
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#include "trace/generated-events.h"
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/**
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* TraceEventID:
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*
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* Unique tracing event identifier.
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*
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* These are named as 'TRACE_${EVENT_NAME}'.
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*
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* See also: "trace/generated-events.h"
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*/
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enum TraceEventID;
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/**
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* trace_event_id:
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* @id: Event identifier.
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*
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* Get an event by its identifier.
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*
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* This routine has a constant cost, as opposed to trace_event_name and
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* trace_event_pattern.
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*
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* Pre-conditions: The identifier is valid.
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*
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* Returns: pointer to #TraceEvent.
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*
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*/
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static TraceEvent *trace_event_id(TraceEventID id);
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/**
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* trace_event_name:
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* @id: Event name.
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*
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* Search an event by its name.
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*
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* Returns: pointer to #TraceEvent or NULL if not found.
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*/
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TraceEvent *trace_event_name(const char *name);
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/**
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* trace_event_pattern:
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* @pat: Event name pattern.
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* @ev: Event to start searching from (not included).
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*
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* Get all events with a given name pattern.
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*
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* Returns: pointer to #TraceEvent or NULL if not found.
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*/
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TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev);
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/**
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* trace_event_is_pattern:
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*
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* Whether the given string is an event name pattern.
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*/
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static bool trace_event_is_pattern(const char *str);
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/**
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* trace_event_count:
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*
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* Return the number of events.
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*/
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static TraceEventID trace_event_count(void);
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/**
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* trace_event_get_id:
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*
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* Get the identifier of an event.
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*/
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static TraceEventID trace_event_get_id(TraceEvent *ev);
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/**
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* trace_event_get_name:
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*
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* Get the name of an event.
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*/
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static const char * trace_event_get_name(TraceEvent *ev);
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/**
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* trace_event_get_state:
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* @id: Event identifier.
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*
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* Get the tracing state of an event (both static and dynamic).
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*
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* If the event has the disabled property, the check will have no performance
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* impact.
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*
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* As a down side, you must always use an immediate #TraceEventID value.
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*/
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#define trace_event_get_state(id) \
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((id ##_ENABLED) && trace_event_get_state_dynamic(trace_event_id(id)))
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/**
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* trace_event_get_state_static:
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* @id: Event identifier.
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*
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* Get the static tracing state of an event.
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*
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* Use the define 'TRACE_${EVENT_NAME}_ENABLED' for compile-time checks (it will
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* be set to 1 or 0 according to the presence of the disabled property).
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*/
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static bool trace_event_get_state_static(TraceEvent *ev);
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/**
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* trace_event_get_state_dynamic:
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*
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* Get the dynamic tracing state of an event.
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*/
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static bool trace_event_get_state_dynamic(TraceEvent *ev);
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/**
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* trace_event_set_state:
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*
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* Set the tracing state of an event (only if possible).
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*/
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#define trace_event_set_state(id, state) \
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do { \
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if ((id ##_ENABLED)) { \
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TraceEvent *_e = trace_event_id(id); \
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trace_event_set_state_dynamic(_e, state); \
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} \
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} while (0)
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/**
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* trace_event_set_state_dynamic:
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*
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* Set the dynamic tracing state of an event.
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*
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* Pre-condition: trace_event_get_state_static(ev) == true
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*/
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static void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
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/**
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* trace_print_events:
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*
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* Print the state of all events.
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*/
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void trace_print_events(FILE *stream, fprintf_function stream_printf);
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/**
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* trace_init_backends:
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* @events: Name of file with events to be enabled at startup; may be NULL.
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* Corresponds to commandline option "-trace events=...".
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* @file: Name of trace output file; may be NULL.
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* Corresponds to commandline option "-trace file=...".
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*
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* Initialize the tracing backend.
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*
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* Returns: Whether the backends could be successfully initialized.
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*/
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bool trace_init_backends(const char *events, const char *file);
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#include "trace/control-internal.h"
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#endif /* TRACE__CONTROL_H */
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