@@ -108,6 +108,27 @@ portability macros, ensure they are preceded and followed by double quotes:
of trace events. Marking trace events disabled by default saves the user
from having to manually disable noisy trace events.
+== Generic interface and monitor commands ==
+
+You can programmatically query and control the dynamic state of trace events
+through a backend-agnostic interface:
+
+* trace_print_events
+
+* trace_event_set_state
+
+Note that some of the backends do not provide and implementation for this
+interface, in which case QEMU will just print a warning.
+
+This functionality is also provided 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.
+
== Trace backends ==
The "tracetool" script automates tedious trace event code generation and also
@@ -157,27 +178,9 @@ unless you have specific needs for more advanced backends.
flushed and emptied. This means the 'info trace' will display few or no
entries if the buffer has just been flushed.
-* 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.
-
* trace-file on|off|flush|set <path>
Enable/disable/flush the trace file or set the trace file name.
-==== Enabling/disabling trace events programmatically ====
-
-The st_change_trace_event_state() function can be used to enable or disable trace
-events at runtime inside QEMU:
-
- #include "trace.h"
-
- st_change_trace_event_state("virtio_irq", true); /* enable */
- [...]
- st_change_trace_event_state("virtio_irq", false); /* disable */
-
==== Analyzing trace files ====
The "simple" backend produces binary trace files that can be formatted with the
@@ -180,7 +180,6 @@ STEXI
Output logs to @var{filename}.
ETEXI
-#ifdef CONFIG_TRACE_SIMPLE
{
.name = "trace-event",
.args_type = "name:s,option:b",
@@ -195,6 +194,7 @@ STEXI
changes status of a trace event
ETEXI
+#if defined(CONFIG_SIMPLE_TRACE)
{
.name = "trace-file",
.args_type = "op:s?,arg:F?",
@@ -1358,10 +1358,13 @@ ETEXI
STEXI
@item info trace
show contents of trace buffer
+ETEXI
+#endif
+
+STEXI
@item info trace-events
show available trace events and their state
ETEXI
-#endif
STEXI
@end table
@@ -57,8 +57,9 @@
#include "json-parser.h"
#include "osdep.h"
#include "cpu.h"
+#include "trace/control.h"
#ifdef CONFIG_TRACE_SIMPLE
-#include "trace.h"
+#include "trace/simple.h"
#endif
#include "trace/control.h"
#include "ui/qemu-spice.h"
@@ -593,7 +594,6 @@ static void do_help_cmd(Monitor *mon, const QDict *qdict)
help_cmd(mon, qdict_get_try_str(qdict, "name"));
}
-#ifdef CONFIG_TRACE_SIMPLE
static void do_trace_event_set_state(Monitor *mon, const QDict *qdict)
{
const char *tp_name = qdict_get_str(qdict, "name");
@@ -605,6 +605,7 @@ static void do_trace_event_set_state(Monitor *mon, const QDict *qdict)
}
}
+#ifdef CONFIG_SIMPLE_TRACE
static void do_trace_file(Monitor *mon, const QDict *qdict)
{
const char *op = qdict_get_try_str(qdict, "op");
@@ -1002,12 +1003,12 @@ static void do_info_trace(Monitor *mon)
{
st_print_trace((FILE *)mon, &monitor_fprintf);
}
+#endif
static void do_trace_print_events(Monitor *mon)
{
trace_print_events((FILE *)mon, &monitor_fprintf);
}
-#endif
/**
* do_quit(): Quit QEMU execution
@@ -3144,6 +3145,7 @@ static const mon_cmd_t info_cmds[] = {
.help = "show current contents of trace buffer",
.mhandler.info = do_info_trace,
},
+#endif
{
.name = "trace-events",
.args_type = "",
@@ -3151,7 +3153,6 @@ static const mon_cmd_t info_cmds[] = {
.help = "show available trace-events & their state",
.mhandler.info = do_trace_print_events,
},
-#endif
{
.name = NULL,
},
The current interface is generic for this small set of operations, and thus other backends can easily modify the "trace/control.c" file to add their own implementation. Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu> --- docs/tracing.txt | 39 +++++++++++++++++++++------------------ hmp-commands.hx | 7 +++++-- monitor.c | 9 +++++---- 3 files changed, 31 insertions(+), 24 deletions(-)