Don't allow specification of needStack to EventPipeProvider when creating an event. (#11571)

Author: brianrob

src/scripts/genEventPipe.py

@@ -136,14 +136,9 @@ def generateClrEventPipeWriteEventsImpl(
         eventLevel = eventLevel.replace("win:", "EventPipeEventLevel::")
         exclusionInfo = parseExclusionList(exclusionListFile)
         taskName = eventNode.getAttribute('task')
-        noStack = getStackWalkBit(
-            providerName,
-            taskName,
-            eventName,
-            exclusionInfo.nostack)
-
-        initEvent = """    EventPipeEvent%s = EventPipeProvider%s->AddEvent(%s,%s,%s,%s,%d);
-""" % (eventName, providerPrettyName, eventKeywordsMask, eventValue, eventVersion, eventLevel, int(noStack))
+
+        initEvent = """    EventPipeEvent%s = EventPipeProvider%s->AddEvent(%s,%s,%s,%s);
+""" % (eventName, providerPrettyName, eventKeywordsMask, eventValue, eventVersion, eventLevel)
 
         WriteEventImpl.append(initEvent)
     WriteEventImpl.append("}")

src/vm/eventpipeprovider.cpp

@@ -128,6 +128,19 @@ void EventPipeProvider::SetConfiguration(bool providerEnabled, INT64 keywords, E
     InvokeCallback();
 }
 
+EventPipeEvent* EventPipeProvider::AddEvent(INT64 keywords, unsigned int eventID, unsigned int eventVersion, EventPipeEventLevel level)
+{
+    CONTRACTL
+    {
+        THROWS;
+        GC_NOTRIGGER;
+        MODE_ANY;
+    }
+    CONTRACTL_END;
+
+    return AddEvent(keywords, eventID, eventVersion, level, true /* needStack */);
+}
+
 EventPipeEvent* EventPipeProvider::AddEvent(INT64 keywords, unsigned int eventID, unsigned int eventVersion, EventPipeEventLevel level, bool needStack)
 {
     CONTRACTL

src/vm/eventpipeprovider.h

@@ -26,6 +26,7 @@ class EventPipeProvider
 {
     // Declare friends.
     friend class EventPipeConfiguration;
+    friend class SampleProfiler;
 
 private:
     // The GUID of the provider.
@@ -71,10 +72,17 @@ class EventPipeProvider
     bool EventEnabled(INT64 keywords, EventPipeEventLevel eventLevel) const;
 
     // Create a new event.
-    EventPipeEvent* AddEvent(INT64 keywords, unsigned int eventID, unsigned int eventVersion, EventPipeEventLevel level, bool needStack);
+    EventPipeEvent* AddEvent(INT64 keywords, unsigned int eventID, unsigned int eventVersion, EventPipeEventLevel level);
 
 private:
 
+    // Create a new event, but allow needStack to be specified.
+    // In general, we want stack walking to be controlled by the consumer and not the producer of events.
+    // However, there are a couple of cases that we know we don't want to do a stackwalk that would affect performance significantly:
+    // 1. Sample profiler events: The sample profiler already does a stack walk of the target thread.  Doing one of the sampler thread is a waste.
+    // 2. Metadata events: These aren't as painful but because we have to keep this functionality around, might as well use it.
+    EventPipeEvent* AddEvent(INT64 keywords, unsigned int eventID, unsigned int eventVersion, EventPipeEventLevel level, bool needStack);
+
     // Add an event to the provider.
     void AddEvent(EventPipeEvent &event);