Bug 1559220 - Special case IndexedDB threads in wakeup telemetry, r=erahm

The approach isn't perhaps super elegant, but it is a small and simple tweak.

Differential Revision: https://phabricator.services.mozilla.com/D34923

--HG--
extra : moz-landing-system : lando

dom/indexedDB/ActorsParent.cpp

@@ -11170,6 +11170,8 @@ bool ConnectionPool::ScheduleTransaction(TransactionInfo* aTransactionInfo,
         nsresult rv = NS_NewNamedThread(runnable->GetThreadName(),
                                         getter_AddRefs(newThread), runnable);
         if (NS_SUCCEEDED(rv)) {
+          newThread->SetNameForWakeupTelemetry(
+              NS_LITERAL_CSTRING("IndexedDB (all)"));
           MOZ_ASSERT(newThread);
 
           IDB_DEBUG_LOG(("ConnectionPool created thread %" PRIu32,

xpcom/threads/LazyIdleThread.cpp

@@ -445,6 +445,11 @@ LazyIdleThread::GetLastLongNonIdleTaskEnd(TimeStamp* _retval) {
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
+NS_IMETHODIMP
+LazyIdleThread::SetNameForWakeupTelemetry(const nsACString& aName) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
 NS_IMETHODIMP
 LazyIdleThread::AsyncShutdown() {
   ASSERT_OWNING_THREAD();

xpcom/threads/nsIThread.idl

@@ -176,4 +176,6 @@ interface nsIThread : nsISerialEventTarget
    */
   [noscript] readonly attribute TimeStamp lastLongTaskEnd;
   [noscript] readonly attribute TimeStamp lastLongNonIdleTaskEnd;
+
+  [noscript] void setNameForWakeupTelemetry(in ACString name);
 };

xpcom/threads/nsThread.cpp

@@ -779,6 +779,14 @@ nsThread::GetLastLongNonIdleTaskEnd(TimeStamp* _retval) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsThread::SetNameForWakeupTelemetry(const nsACString& aName) {
+#ifdef EARLY_BETA_OR_EARLIER
+  mNameForWakeupTelemetry = aName;
+#endif
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsThread::AsyncShutdown() {
   LOG(("THRD(%p) async shutdown\n", this));
@@ -1137,7 +1145,9 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult) {
           if (ms < 0) {
             ms = 0;
           }
-          const char* name = PR_GetThreadName(mThread);
+          const char* name = !mNameForWakeupTelemetry.IsEmpty()
+                                 ? mNameForWakeupTelemetry.get()
+                                 : PR_GetThreadName(mThread);
           if (!name) {
             name = IsMainThread() ? "MainThread" : "(nameless thread)";
           }

xpcom/threads/nsThread.h

@@ -245,6 +245,7 @@ class nsThread : public nsIThreadInternal,
   mozilla::TimeStamp mNextIdleDeadline;
 
 #ifdef EARLY_BETA_OR_EARLIER
+  nsCString mNameForWakeupTelemetry;
   mozilla::TimeStamp mLastWakeupCheckTime;
   uint32_t mWakeupCount = 0;
 #endif