trace: dynamically allocate event IDs at runtime

Instead of having the code generator assign event IDs and event VCPU IDs, assign them when the events are registered at runtime. This will allow code to be generated from individual trace-events without having to figure out globally unique numbering at build time. Reviewed-by: Stefan Hajnoczi <[email protected]> Reviewed-by: Lluís Vilanova <[email protected]> Signed-off-by: Daniel P. Berrange <[email protected]> Message-id: [email protected] Signed-off-by: Stefan Hajnoczi <[email protected]>
xiaolou86 · Oct 12, 2016 · ca3fa0e · ca3fa0e
1 parent b7d4895
commit ca3fa0e
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Showing 3 changed files with 12 additions and 13 deletions.
diff --git a/scripts/tracetool/format/events_c.py b/scripts/tracetool/format/events_c.py
@@ -28,25 +28,19 @@ def generate(events, backend):
     for e in events:
         out('uint16_t %s;' % e.api(e.QEMU_DSTATE))
 
-    next_id = 0
-    next_vcpu_id = 0
     for e in events:
-        id = next_id
-        next_id += 1
         if "vcpu" in e.properties:
-            vcpu_id = next_vcpu_id
-            next_vcpu_id += 1
+            vcpu_id = 0
         else:
             vcpu_id = "TRACE_VCPU_EVENT_NONE"
         out('TraceEvent %(event)s = {',
-            '    .id = %(id)s,',
+            '    .id = 0,',
             '    .vcpu_id = %(vcpu_id)s,',
             '    .name = \"%(name)s\",',
             '    .sstate = %(sstate)s,',
             '    .dstate = &%(dstate)s ',
             '};',
             event = e.api(e.QEMU_EVENT),
-            id = id,
             vcpu_id = vcpu_id,
             name = e.name,
             sstate = "TRACE_%s_ENABLED" % e.name.upper(),

diff --git a/scripts/tracetool/format/events_h.py b/scripts/tracetool/format/events_h.py
@@ -32,10 +32,6 @@ def generate(events, backend):
     for e in events:
         out('extern uint16_t %s;' % e.api(e.QEMU_DSTATE))
 
-    numvcpu = len([e for e in events if "vcpu" in e.properties])
-
-    out("#define TRACE_VCPU_EVENT_COUNT %d" % numvcpu)
-
     # static state
     for e in events:
         if 'disable' in e.properties:

diff --git a/trace/control.c b/trace/control.c
@@ -35,6 +35,8 @@ typedef struct TraceEventGroup {
 
 static TraceEventGroup *event_groups;
 static size_t nevent_groups;
+static uint32_t next_id;
+static uint32_t next_vcpu_id;
 
 QemuOptsList qemu_trace_opts = {
     .name = "trace",
@@ -59,6 +61,13 @@ QemuOptsList qemu_trace_opts = {
 
 void trace_event_register_group(TraceEvent **events)
 {
+    size_t i;
+    for (i = 0; events[i] != NULL; i++) {
+        events[i]->id = next_id++;
+        if (events[i]->vcpu_id != TRACE_VCPU_EVENT_NONE) {
+            events[i]->vcpu_id = next_vcpu_id++;
+        }
+    }
     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
     event_groups[nevent_groups].events = events;
     nevent_groups++;
@@ -293,5 +302,5 @@ char *trace_opt_parse(const char *optarg)
 
 uint32_t trace_get_vcpu_event_count(void)
 {
-    return TRACE_VCPU_EVENT_COUNT;
+    return next_vcpu_id;
 }