This interface decouples event obtaining from interaction.
Events can be obtained through three different methods:
* identifier
* name
* simple wildcard pattern
Signed-off-by: Lluís Vilanova <vilan...@ac.upc.edu>
---
docs/tracing.txt | 44 ++++-------
trace/control-internal.h | 67 ++++++++++++++++
trace/control.c | 106 +++++++++++++++++++++++---
trace/control.h | 190 +++++++++++++++++++++++++++++++++++++++++-----
4 files changed, 349 insertions(+), 58 deletions(-)
create mode 100644 trace/control-internal.h
diff --git a/docs/tracing.txt b/docs/tracing.txt
index 14db3bf..cf53c17 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -100,49 +100,37 @@ respectively. This ensures portability between 32- and
64-bit platforms.
== Generic interface and monitor commands ==
-You can programmatically query and control the dynamic state of trace events
-through a backend-agnostic interface:
+You can programmatically query and control the state of trace events through a
+backend-agnostic interface provided by the header "trace/control.h".
-* trace_print_events
+Note that some of the backends do not provide an implementation for some parts
+of this interface, in which case QEMU will just print a warning (please refer
to
+header "trace/control.h" to see which routines are backend-dependent).
-* trace_event_set_state
- Enables or disables trace events at runtime inside QEMU.
- The function returns "true" if the state of the event has been successfully
- changed, or "false" otherwise:
-
- #include "trace/control.h"
-
- trace_event_set_state("virtio_irq", true); /* enable */
- [...]
- trace_event_set_state("virtio_irq", false); /* disable */
-
-Note that some of the backends do not provide an implementation for this
-interface, in which case QEMU will just print a warning.
-
-This functionality is also provided through monitor commands:
+The state of events can also be queried and modified through monitor commands:
* info trace-events
View available trace events and their state. State 1 means enabled, state 0
means disabled.
* trace-event NAME on|off
- Enable/disable a given trace event or a group of events having common prefix
- through wildcard.
+ Enable/disable a given trace event or a group of events (using wildcards).
The "-trace events=<file>" command line argument can be used to enable the
events listed in <file> from the very beginning of the program. This file must
contain one event name per line.
-A basic wildcard matching is supported in both the monitor command "trace
--event" and the events list file. That means you can enable/disable the events
-having a common prefix in a batch. For example, virtio-blk trace events could
-be enabled using:
- trace-event virtio_blk_* on
-
If a line in the "-trace events=<file>" file begins with a '-', the trace event
will be disabled instead of enabled. This is useful when a wildcard was used
to enable an entire family of events but one noisy event needs to be disabled.
+Wildcard matching is supported in both the monitor command "trace-event" and
the
+events list file. That means you can enable/disable the events having a common
+prefix in a batch. For example, virtio-blk trace events could be enabled using
+the following monitor command:
+
+ trace-event virtio_blk_* on
+
== Trace backends ==
The "tracetool" script automates tedious trace event code generation and also
@@ -263,3 +251,7 @@ guard such computations and avoid its compilation when the
event is disabled:
}
return ptr;
}
+
+You can check both if the event has been disabled and is dynamically enabled at
+the same time using the 'trace_event_get_state' routine (see header
+"trace/control.h" for more information).
diff --git a/trace/control-internal.h b/trace/control-internal.h
new file mode 100644
index 0000000..cce2da4
--- /dev/null
+++ b/trace/control-internal.h
@@ -0,0 +1,67 @@
+/*
+ * Interface for configuring and controlling the state of tracing events.
+ *
+ * Copyright (C) 2011-2012 Lluís Vilanova <vilan...@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_INTERNAL_H
+#define TRACE__CONTROL_INTERNAL_H
+
+#include <string.h>
+
+
+extern TraceEvent trace_events[];
+
+
+static inline TraceEvent *trace_event_id(TraceEventID id)
+{
+ assert(id < trace_event_count());
+ return &trace_events[id];
+}
+
+static inline TraceEventID trace_event_count(void)
+{
+ return TRACE_EVENT_COUNT;
+}
+
+static inline bool trace_event_is_pattern(const char *str)
+{
+ assert(str != NULL);
+ return strchr(str, '*') != NULL;
+}
+
+static inline TraceEventID trace_event_get_id(TraceEvent *ev)
+{
+ assert(ev != NULL);
+ return ev->id;
+}
+
+static inline const char * trace_event_get_name(TraceEvent *ev)
+{
+ assert(ev != NULL);
+ return ev->name;
+}
+
+static inline bool trace_event_get_state_static(TraceEvent *ev)
+{
+ assert(ev != NULL);
+ return ev->sstate;
+}
+
+static inline bool trace_event_get_state_dynamic(TraceEvent *ev)
+{
+ assert(ev != NULL);
+ return ev->dstate;
+}
+
+static inline void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
+{
+ assert(ev != NULL);
+ assert(trace_event_get_state_static(ev));
+ return trace_event_set_state_dynamic_backend(ev, state);
+}
+
+#endif /* TRACE__CONTROL_INTERNAL_H */
diff --git a/trace/control.c b/trace/control.c
index be05efb..49f61e1 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -1,19 +1,86 @@
/*
* Interface for configuring and controlling the state of tracing events.
*
- * Copyright (C) 2011 Lluís Vilanova <vilan...@ac.upc.edu>
+ * Copyright (C) 2011-2012 Lluís Vilanova <vilan...@ac.upc.edu>
*
- * This work is licensed under the terms of the GNU GPL, version 2. See
- * the COPYING file in the top-level directory.
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
*/
#include "trace/control.h"
-void trace_backend_init_events(const char *fname)
+TraceEvent *trace_event_name(const char *name)
+{
+ assert(name != NULL);
+
+ TraceEventID i;
+ for (i = 0; i < trace_event_count(); i++) {
+ TraceEvent *ev = trace_event_id(i);
+ if (strcmp(trace_event_get_name(ev), name) == 0) {
+ return ev;
+ }
+ }
+ return NULL;
+}
+
+static bool pattern_glob(const char *pat, const char *ev)
+{
+ while (*pat != '\0' && *ev != '\0') {
+ if (*pat == *ev) {
+ pat++;
+ ev++;
+ }
+ else if (*pat == '*') {
+ if (pattern_glob(pat, ev+1)) {
+ return true;
+ } else if (pattern_glob(pat+1, ev)) {
+ return true;
+ } else {
+ return false;
+ }
+ } else {
+ return false;
+ }
+ }
+
+ while (*pat == '*') {
+ pat++;
+ }
+
+ if (*pat == '\0' && *ev == '\0') {
+ return true;
+ } else {
+ return false;
+ }
+}
+
+TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
{
- int ret;
+ assert(pat != NULL);
+ TraceEventID i;
+
+ if (ev == NULL) {
+ i = -1;
+ } else {
+ i = trace_event_get_id(ev);
+ }
+ i++;
+
+ while (i < trace_event_count()) {
+ TraceEvent *res = trace_event_id(i);
+ if (pattern_glob(pat, trace_event_get_name(res))) {
+ return res;
+ }
+ i++;
+ }
+
+ return NULL;
+}
+
+void trace_backend_init_events(const char *fname)
+{
if (fname == NULL) {
return;
}
@@ -32,15 +99,28 @@ void trace_backend_init_events(const char *fname)
if ('#' == line_buf[0]) { /* skip commented lines */
continue;
}
- if ('-' == line_buf[0]) {
- ret = trace_event_set_state(line_buf+1, false);
+ const bool enable = ('-' != line_buf[0]);
+ char *line_ptr = enable ? line_buf : line_buf + 1;
+ if (trace_event_is_pattern(line_ptr)) {
+ TraceEvent *ev = NULL;
+ while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
+ if (trace_event_get_state_static(ev)) {
+ trace_event_set_state_dynamic(ev, enable);
+ }
+ }
} else {
- ret = trace_event_set_state(line_buf, true);
- }
- if (!ret) {
- fprintf(stderr,
- "error: trace event '%s' does not exist\n", line_buf);
- exit(1);
+ TraceEvent *ev = trace_event_name(line_ptr);
+ if (ev == NULL) {
+ fprintf(stderr,
+ "error: trace event '%s' does not exist\n",
line_ptr);
+ exit(1);
+ }
+ if (!trace_event_get_state_static(ev)) {
+ fprintf(stderr,
+ "error: trace event '%s' is not traceable\n",
line_ptr);
+ exit(1);
+ }
+ trace_event_set_state_dynamic(ev, enable);
}
}
}
diff --git a/trace/control.h b/trace/control.h
index 2acaa42..cde8260 100644
--- a/trace/control.h
+++ b/trace/control.h
@@ -1,41 +1,193 @@
/*
* Interface for configuring and controlling the state of tracing events.
*
- * Copyright (C) 2011 Lluís Vilanova <vilan...@ac.upc.edu>
+ * Copyright (C) 2011-2012 Lluís Vilanova <vilan...@ac.upc.edu>
*
- * This work is licensed under the terms of the GNU GPL, version 2. See
- * the COPYING file in the top-level directory.
+ * 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
+#ifndef TRACE__CONTROL_H
+#define TRACE__CONTROL_H
#include "qemu-common.h"
+#include "trace/generated-events.h"
-/** Print the state of all events. */
-void trace_print_events(FILE *stream, fprintf_function stream_printf);
-/** Set the state of an event.
+/**
+ * TraceEventID:
+ *
+ * Unique tracing event identifier.
+ *
+ * These are named as 'TRACE_${EVENT_NAME}'.
+ *
+ * See also: "trace/generated-events.h"
+ */
+enum TraceEventID;
+
+/**
+ * trace_event_id:
+ * @id: Event identifier.
+ *
+ * Get an event by its identifier.
+ *
+ * This routine has a constant cost, as opposed to trace_event_name and
+ * trace_event_pattern.
+ *
+ * Pre-conditions: The identifier is valid.
+ *
+ * Returns: pointer to #TraceEvent.
+ *
+ */
+static TraceEvent *trace_event_id(TraceEventID id);
+
+/**
+ * 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_pattern:
+ * @pat: Event name pattern.
+ * @ev: Event to start searching from (not included).
+ *
+ * Get all events with a given name pattern.
+ *
+ * Returns: pointer to #TraceEvent or NULL if not found.
+ */
+TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev);
+
+/**
+ * trace_event_is_pattern:
+ *
+ * Whether the given string is an event name pattern.
+ */
+static bool trace_event_is_pattern(const char *str);
+
+/**
+ * trace_event_count:
+ *
+ * Return the number of events.
+ */
+static TraceEventID trace_event_count(void);
+
+
+
+/**
+ * trace_event_get_id:
+ *
+ * Get the identifier of an event.
+ */
+static TraceEventID trace_event_get_id(TraceEvent *ev);
+
+/**
+ * trace_event_get_name:
*
- * @return Whether the state changed.
+ * Get the name of an event.
*/
-bool trace_event_set_state(const char *name, bool state);
+static const char * trace_event_get_name(TraceEvent *ev);
+/**
+ * trace_event_get_state:
+ * @id: Event identifier.
+ *
+ * Get the tracing state of an event (both static and dynamic).
+ *
+ * If the event has the disabled property, the check will have no performance
+ * impact.
+ *
+ * As a down side, you must always use an immediate #TraceEventID value.
+ */
+#define trace_event_get_state(id) \
+ ((id ##_ENABLED) && trace_event_get_state_dynamic(trace_event_id(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.
+ */
+static bool trace_event_get_state_dynamic(TraceEvent *ev);
+
+/**
+ * trace_event_set_state:
+ *
+ * Set the tracing state of an event (only if possible).
+ */
+#define trace_event_set_state(id, state) \
+ do { \
+ if ((id ##_ENABLED)) { \
+ TraceEvent *_e = trace_event_id(id); \
+ trace_event_set_state_dynamic(_e, state); \
+ } \
+ } while (0)
+
+/**
+ * trace_event_set_state_dynamic:
+ *
+ * Set the dynamic tracing state of an event.
+ *
+ * Pre-condition: trace_event_get_state_static(ev) == true
+ */
+static void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
+
+/**
+ * trace_event_set_state_dynamic_backend:
+ *
+ * Warning: This function must be implemented by each tracing backend.
+ */
+void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state);
+
+
+
+/**
+ * trace_print_events:
+ *
+ * Print the state of all events.
+ *
+ * Warning: This function must be implemented by each tracing backend.
+ */
+void trace_print_events(FILE *stream, fprintf_function stream_printf);
-/** Initialize the tracing backend.
+/**
+ * trace_backend_init:
+ * @events: Name of file with events to be enabled at startup; may be NULL.
+ * Corresponds to commandline option "-trace events=...".
+ * @file: Name of trace output file; may be NULL.
+ * Corresponds to commandline option "-trace file=...".
*
- * @events Name of file with events to be enabled at startup; may be NULL.
- * Corresponds to commandline option "-trace events=...".
- * @file Name of trace output file; may be NULL.
- * Corresponds to commandline option "-trace file=...".
- * @return Whether the backend could be successfully initialized.
+ * Initialize the tracing backend.
+ *
+ * Warning: This function must be implemented by each tracing backend.
+ *
+ * Returns: Whether the backend could be successfully initialized.
*/
bool trace_backend_init(const char *events, const char *file);
-/** Generic function to initialize the state of events.
+/**
+ * trace_backend_init_events:
+ * @fname: Name of file with events to enable; may be NULL.
*
- * @fname Name of file with events to enable; may be NULL.
+ * Generic function to initialize the state of events.
*/
void trace_backend_init_events(const char *fname);
-#endif /* TRACE_CONTROL_H */
+
+#include "trace/control-internal.h"
+
+#endif /* TRACE__CONTROL_H */
