trace: Multi-backend tracing

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>

1 files changed, 1 insertions, 18 deletions

diff --git a/trace/simple.c b/trace/simple.c
index 5a2e188c9a..a8f923c82e 100644
--- a/trace/simple.c
+++ b/trace/simple.c
@@ -368,22 +368,6 @@ void st_flush_trace_buffer(void)
     flush_trace_file(true);
 }
 
-void trace_print_events(FILE *stream, fprintf_function stream_printf)
-{
-    unsigned int i;
-
-    for (i = 0; i < trace_event_count(); i++) {
-        TraceEvent *ev = trace_event_id(i);
-        stream_printf(stream, "%s [Event ID %u] : state %u\n",
-                      trace_event_get_name(ev), i, trace_event_get_state_dynamic(ev));
-    }
-}
-
-void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state)
-{
-    ev->dstate = state;
-}
-
 /* Helper function to create a thread with signals blocked.  Use glib's
  * portable threads since QEMU abstractions cannot be used due to reentrancy in
  * the tracer.  Also note the signal masking on POSIX hosts so that the thread
@@ -412,7 +396,7 @@ static GThread *trace_thread_create(GThreadFunc fn)
     return thread;
 }
 
-bool trace_backend_init(const char *events, const char *file)
+bool st_init(const char *file)
 {
     GThread *thread;
 
@@ -430,7 +414,6 @@ bool trace_backend_init(const char *events, const char *file)
     }
 
     atexit(st_flush_trace_buffer);
-    trace_backend_init_events(events);
     st_set_trace_file(file);
     return true;
 }