qemu/trace/control.h
Stefan Hajnoczi d87aa13803 trace: add trace_event_get_state_backends()
Code that checks dstate is unaware of SystemTap and LTTng UST dstate, so
the following trace event will not fire when solely enabled by SystemTap
or LTTng UST:

  if (trace_event_get_state(TRACE_MY_EVENT)) {
      str = g_strdup_printf("Expensive string to generate ...",
                            ...);
      trace_my_event(str);
      g_free(str);
  }

Add trace_event_get_state_backends() to fetch backend dstate.  Those
backends that use QEMU dstate fetch it as part of
generate_h_backend_dstate().

Update existing trace_event_get_state() callers to use
trace_event_get_state_backends() instead.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170731140718.22010-3-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-08-01 12:13:07 +01:00

273 lines
6.7 KiB
C

/*
* Interface for configuring and controlling the state of tracing events.
*
* Copyright (C) 2011-2016 Lluís Vilanova <vilanova@ac.upc.edu>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef TRACE__CONTROL_H
#define TRACE__CONTROL_H
#include "qemu-common.h"
#include "event-internal.h"
typedef struct TraceEventIter {
size_t event;
size_t group;
const char *pattern;
} TraceEventIter;
/**
* trace_event_iter_init:
* @iter: the event iterator struct
* @pattern: optional pattern to filter events on name
*
* Initialize the event iterator struct @iter,
* optionally using @pattern to filter out events
* with non-matching names.
*/
void trace_event_iter_init(TraceEventIter *iter, const char *pattern);
/**
* trace_event_iter_next:
* @iter: the event iterator struct
*
* Get the next event, if any. When this returns NULL,
* the iterator should no longer be used.
*
* Returns: the next event, or NULL if no more events exist
*/
TraceEvent *trace_event_iter_next(TraceEventIter *iter);
/**
* trace_event_name:
* @id: Event name.
*
* Search an event by its name.
*
* Returns: pointer to #TraceEvent or NULL if not found.
*/
TraceEvent *trace_event_name(const char *name);
/**
* trace_event_is_pattern:
*
* Whether the given string is an event name pattern.
*/
static bool trace_event_is_pattern(const char *str);
/**
* trace_event_get_id:
*
* Get the identifier of an event.
*/
static uint32_t trace_event_get_id(TraceEvent *ev);
/**
* trace_event_get_vcpu_id:
*
* Get the per-vCPU identifier of an event.
*
* Special value #TRACE_VCPU_EVENT_NONE means the event is not vCPU-specific
* (does not have the "vcpu" property).
*/
static uint32_t trace_event_get_vcpu_id(TraceEvent *ev);
/**
* trace_event_is_vcpu:
*
* Whether this is a per-vCPU event.
*/
static bool trace_event_is_vcpu(TraceEvent *ev);
/**
* trace_event_get_name:
*
* Get the name of an event.
*/
static const char * trace_event_get_name(TraceEvent *ev);
/**
* trace_event_get_state:
* @id: Event identifier name.
*
* Get the tracing state of an event, both static and the QEMU dynamic state.
*
* If the event has the disabled property, the check will have no performance
* impact.
*/
#define trace_event_get_state(id) \
((id ##_ENABLED) && trace_event_get_state_dynamic_by_id(id))
/**
* trace_event_get_state_backends:
* @id: Event identifier name.
*
* Get the tracing state of an event, both static and dynamic state from all
* compiled-in backends.
*
* If the event has the disabled property, the check will have no performance
* impact.
*
* Returns: true if at least one backend has the event enabled and the event
* does not have the disabled property.
*/
#define trace_event_get_state_backends(id) \
((id ##_ENABLED) && id ##_BACKEND_DSTATE())
/**
* trace_event_get_vcpu_state:
* @vcpu: Target vCPU.
* @id: Event identifier name.
*
* Get the tracing state of an event (both static and dynamic) for the given
* vCPU.
*
* If the event has the disabled property, the check will have no performance
* impact.
*/
#define trace_event_get_vcpu_state(vcpu, id) \
((id ##_ENABLED) && \
trace_event_get_vcpu_state_dynamic_by_vcpu_id( \
vcpu, _ ## id ## _EVENT.vcpu_id))
/**
* trace_event_get_state_static:
* @id: Event identifier.
*
* Get the static tracing state of an event.
*
* Use the define 'TRACE_${EVENT_NAME}_ENABLED' for compile-time checks (it will
* be set to 1 or 0 according to the presence of the disabled property).
*/
static bool trace_event_get_state_static(TraceEvent *ev);
/**
* trace_event_get_state_dynamic:
*
* Get the dynamic tracing state of an event.
*
* If the event has the 'vcpu' property, gets the OR'ed state of all vCPUs.
*/
static bool trace_event_get_state_dynamic(TraceEvent *ev);
/**
* trace_event_get_vcpu_state_dynamic:
*
* Get the dynamic tracing state of an event for the given vCPU.
*/
static bool trace_event_get_vcpu_state_dynamic(CPUState *vcpu, TraceEvent *ev);
/**
* trace_event_set_state_dynamic:
*
* Set the dynamic tracing state of an event.
*
* If the event has the 'vcpu' property, sets the state on all vCPUs.
*
* Pre-condition: trace_event_get_state_static(ev) == true
*/
void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
/**
* trace_event_set_vcpu_state_dynamic:
*
* Set the dynamic tracing state of an event for the given vCPU.
*
* Pre-condition: trace_event_get_vcpu_state_static(ev) == true
*
* Note: Changes for execution-time events with the 'tcg' property will not be
* propagated until the next TB is executed (iff executing in TCG mode).
*/
void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
TraceEvent *ev, bool state);
/**
* trace_init_backends:
* @file: Name of trace output file; may be NULL.
* Corresponds to commandline option "-trace file=...".
*
* Initialize the tracing backend.
*
* Returns: Whether the backends could be successfully initialized.
*/
bool trace_init_backends(void);
/**
* trace_init_file:
* @file: Name of trace output file; may be NULL.
* Corresponds to commandline option "-trace file=...".
*
* Record the name of the output file for the tracing backend.
* Exits if no selected backend does not support specifying the
* output file, and a non-NULL file was passed.
*/
void trace_init_file(const char *file);
/**
* trace_init_vcpu:
* @vcpu: Added vCPU.
*
* Set initial dynamic event state for a hot-plugged vCPU.
*/
void trace_init_vcpu(CPUState *vcpu);
/**
* trace_fini_vcpu:
* @vcpu: Removed vCPU.
*
* Disable dynamic event state for a hot-unplugged vCPU.
*/
void trace_fini_vcpu(CPUState *vcpu);
/**
* trace_list_events:
*
* List all available events.
*/
void trace_list_events(void);
/**
* trace_enable_events:
* @line_buf: A string with a glob pattern of events to be enabled or,
* if the string starts with '-', disabled.
*
* Enable or disable matching events.
*/
void trace_enable_events(const char *line_buf);
/**
* Definition of QEMU options describing trace subsystem configuration
*/
extern QemuOptsList qemu_trace_opts;
/**
* trace_opt_parse:
* @optarg: A string argument of --trace command line argument
*
* Initialize tracing subsystem.
*
* Returns the filename to save trace to. It must be freed with g_free().
*/
char *trace_opt_parse(const char *optarg);
/**
* trace_get_vcpu_event_count:
*
* Return the number of known vcpu-specific events
*/
uint32_t trace_get_vcpu_event_count(void);
#include "trace/control-internal.h"
#endif /* TRACE__CONTROL_H */