Backed out changeset 119623addbbd

Summary: Unlanding D6327460 because seems to be causing unstability.

Differential Revision: D6377117

fbshipit-source-id: 4e1241fe65cd4c7a127fa6fa724f60b75965a096

4 files changed, 26 insertions, 15 deletions

diff --git a/caffe2/observers/runcnt_observer.cc b/caffe2/observers/runcnt_observer.cc
index d28a3b7d0b..d52a7d6fa3 100644
--- a/caffe2/observers/runcnt_observer.cc
+++ b/caffe2/observers/runcnt_observer.cc
@@ -18,18 +18,24 @@ std::string RunCountNetObserver::debugInfo() {
   return "This operator runs " + caffe2::to_string(cnt_) + " times.";
 }
 
-void RunCountNetObserver::Start() {
+bool RunCountNetObserver::Start() {
   const auto& operators = subject_->GetOperators();
   for (auto* op : operators) {
     op->AttachObserver(caffe2::make_unique<RunCountOperatorObserver>(op, this));
   }
+  return true;
 }
 
-void RunCountNetObserver::Stop() {}
+bool RunCountNetObserver::Stop() {
+  return true;
+}
 
-void RunCountOperatorObserver::Start() {
+bool RunCountOperatorObserver::Start() {
   ++netObserver_->cnt_;
+  return true;
+}
+bool RunCountOperatorObserver::Stop() {
+  return true;
 }
-void RunCountOperatorObserver::Stop() {}
 
 } // namespace caffe2
diff --git a/caffe2/observers/runcnt_observer.h b/caffe2/observers/runcnt_observer.h
index a27e773a08..44b016a57b 100644
--- a/caffe2/observers/runcnt_observer.h
+++ b/caffe2/observers/runcnt_observer.h
@@ -16,8 +16,8 @@ class RunCountOperatorObserver final : public ObserverBase<OperatorBase> {
   std::unique_ptr<ObserverBase<OperatorBase>> clone() override;
 
  private:
-  void Start() override;
-  void Stop() override;
+  bool Start() override;
+  bool Stop() override;
 
  private:
   RunCountNetObserver* netObserver_;
@@ -34,8 +34,8 @@ class RunCountNetObserver final : public ObserverBase<NetBase> {
   friend class RunCountOperatorObserver;
 
  private:
-  void Start() override;
-  void Stop() override;
+  bool Start() override;
+  bool Stop() override;
 
  protected:
   std::atomic<int> cnt_;
diff --git a/caffe2/observers/time_observer.cc b/caffe2/observers/time_observer.cc
index 80f5a95944..630d632f8f 100644
--- a/caffe2/observers/time_observer.cc
+++ b/caffe2/observers/time_observer.cc
@@ -20,31 +20,35 @@
 namespace caffe2 {
 
 template <>
-void TimeObserverBase<NetBase>::Start() {
+bool TimeObserverBase<NetBase>::Start() {
   CAFFE_THROW(
       "This function is overridden by TimeObserver<NetBase>.\
               If it was called there is an issue with compilation.");
+  return false;
 }
 
 template <>
-void TimeObserverBase<NetBase>::Stop() {
+bool TimeObserverBase<NetBase>::Stop() {
   double current_run = timer_.MilliSeconds() - start_time_;
   total_time_ += current_run;
   VLOG(1) << "This net iteration took " << current_run << " ms to complete.\n";
+  return true;
 }
 
 template <>
-void TimeObserverBase<OperatorBase>::Start() {
+bool TimeObserverBase<OperatorBase>::Start() {
   start_time_ = timer_.MilliSeconds();
   ++iterations_;
+  return true;
 }
 
 template <>
-void TimeObserverBase<OperatorBase>::Stop() {
+bool TimeObserverBase<OperatorBase>::Stop() {
   double current_run = timer_.MilliSeconds() - start_time_;
   total_time_ += current_run;
   VLOG(1) << "This operator iteration took " << current_run
           << " ms to complete.\n";
+  return true;
 }
 
 } // namespace caffe2
diff --git a/caffe2/observers/time_observer.h b/caffe2/observers/time_observer.h
index add88ea19f..10bf0097b0 100644
--- a/caffe2/observers/time_observer.h
+++ b/caffe2/observers/time_observer.h
@@ -36,8 +36,8 @@ class TimeObserverBase : public ObserverBase<T> {
   }
   ~TimeObserverBase() {}
 
-  void Start() override;
-  void Stop() override;
+  bool Start() override;
+  bool Stop() override;
 
  protected:
   Timer timer_;
@@ -77,7 +77,7 @@ class TimeObserver<NetBase> final : public TimeObserverBase<NetBase> {
     return sum / subject_->GetOperators().size();
   }
 
-  void Start() override {
+  bool Start() override {
     for (auto* op : subject_->GetOperators()) {
       const auto* observer = op->AttachObserver(
           caffe2::make_unique<TimeObserver<OperatorBase>>(op));
@@ -87,6 +87,7 @@ class TimeObserver<NetBase> final : public TimeObserverBase<NetBase> {
     }
     start_time_ = timer_.MilliSeconds();
     ++iterations_;
+    return true;
   }
 
  private: