Timing ops are now fences (#789)

src/timing/timing.cc

@@ -53,26 +53,16 @@ std::int64_t Time::value() const { return impl_->value(); }
 
 Time measure_microseconds()
 {
-  auto runtime = Legion::Runtime::get_runtime();
-  auto context = Legion::Runtime::get_context();
-
-  // Capture the completion of all outstanding ops and pass it as a precondition to the timing op
-  auto precondition = runtime->issue_execution_fence(context);
-  auto future       = runtime->get_current_time_in_microseconds(context, precondition);
-
-  return Time{std::make_shared<Time::Impl>(std::move(future))};
+  return Time{
+    std::make_shared<Time::Impl>(Legion::Runtime::get_runtime()->get_current_time_in_microseconds(
+      Legion::Runtime::get_context()))};
 }
 
 Time measure_nanoseconds()
 {
-  auto runtime = Legion::Runtime::get_runtime();
-  auto context = Legion::Runtime::get_context();
-
-  // Capture the completion of all outstanding ops and pass it as a precondition to the timing op
-  auto precondition = runtime->issue_execution_fence(context);
-  auto future       = runtime->get_current_time_in_nanoseconds(context, precondition);
-
-  return Time{std::make_shared<Time::Impl>(std::move(future))};
+  return Time{
+    std::make_shared<Time::Impl>(Legion::Runtime::get_runtime()->get_current_time_in_nanoseconds(
+      Legion::Runtime::get_context()))};
 }
 
 }  // namespace legate::timing