trace: remove global 'uint16 dstate[]' array

Instead of having a global dstate array, declare a single
'uint16 TRACE_${EVENT_NAME}_DSTATE' variable for each
trace event. Record a pointer to this variable in the
TraceEvent struct too.

By turning trace_event_get_state_dynamic_by_id into a
macro, this still hits the fast path, and cache affinity
is ensured by declaring all the uint16 vars adjacent to
each other.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-7-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 4 insertions, 5 deletions

diff --git a/stubs/trace-control.c b/stubs/trace-control.c
index f765a02018..7f856e5c24 100644
--- a/stubs/trace-control.c
+++ b/stubs/trace-control.c
@@ -18,22 +18,21 @@ void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state)
 
 void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
 {
-    TraceEventID id;
     bool state_pre;
     assert(trace_event_get_state_static(ev));
-    id = trace_event_get_id(ev);
+
     /*
      * We ignore the "vcpu" property here, since there's no target code. Then
      * dstate can only be 1 or 0.
      */
-    state_pre = trace_events_dstate[id];
+    state_pre = *(ev->dstate);
     if (state_pre != state) {
         if (state) {
             trace_events_enabled_count++;
-            trace_events_dstate[id] = 1;
+            *(ev->dstate) = 1;
         } else {
             trace_events_enabled_count--;
-            trace_events_dstate[id] = 0;
+            *(ev->dstate) = 0;
         }
     }
 }