trace: Support for dynamically enabling/disabling trace events
This patch adds support for dynamically enabling/disabling of trace events.
This is done by internally maintaining each trace event's state, and
permitting logging of data from a trace event only if it is in an
'active' state.
Monitor commands added :
1) info trace-events : to view all available trace events and
their state.
2) trace-event NAME on|off : to enable/disable data logging from a
given trace event.
Eg, trace-event paio_submit off
disables logging of data when
paio_submit is hit.
By default, all trace-events are disabled. One can enable desired trace-events
via the monitor.
Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
trace: Monitor command 'info trace'
Monitor command 'info trace' to display contents of trace buffer
Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
trace: Remove monitor.h dependency from simpletrace
User-mode targets don't have a monitor so the simple trace backend
currently does not build on those targets. This patch abstracts the
monitor printing interface so there is no direct coupling between
simpletrace and the monitor.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
diff --git a/qemu-monitor.hx b/qemu-monitor.hx
index 5c1da33..c264c7d 100644
--- a/qemu-monitor.hx
+++ b/qemu-monitor.hx
@@ -281,6 +281,22 @@
Output logs to @var{filename}.
ETEXI
+#ifdef CONFIG_SIMPLE_TRACE
+ {
+ .name = "trace-event",
+ .args_type = "name:s,option:b",
+ .params = "name on|off",
+ .help = "changes status of a specific trace event",
+ .mhandler.cmd = do_change_trace_event_state,
+ },
+
+STEXI
+@item trace-event
+@findex trace-event
+changes status of a trace event
+ETEXI
+#endif
+
{
.name = "log",
.args_type = "items:s",
@@ -2529,6 +2545,15 @@
@end table
ETEXI
+#ifdef CONFIG_SIMPLE_TRACE
+STEXI
+@item info trace
+show contents of trace buffer
+@item info trace-events
+show available trace events and their state
+ETEXI
+#endif
+
HXCOMM DO NOT add new commands after 'info', move your addition before it!
STEXI
