Fix for the HHWheelTimer broken Windows build

Summary:
Fix for the HHWheelTimer broken Windows build

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D14642461

fbshipit-source-id: 07292429b1e27eafeb144ab529940aee86dcca6d

folly/io/async/HHWheelTimer.cpp

@@ -27,7 +27,6 @@
 
 
 namespace folly {
-
 /**
  * We want to select the default interval carefully.
  * An interval of 10ms will give us 10ms * WHEEL_SIZE^WHEEL_BUCKETS
@@ -40,8 +39,16 @@ namespace folly {
  * start showing up in cpu perf.  Also, it might not be possible to set
  * tick interval less than 10ms on older kernels.
  */
+
+/*
+ * For high res timers:
+ * An interval of 200usec will give us 200usec * WHEEL_SIZE^WHEEL_BUCKETS
+ * for the largest timeout possible, or about 9 days.
+ */
+
 template <class Duration>
-int HHWheelTimerBase<Duration>::DEFAULT_TICK_INTERVAL = 10;
+int HHWheelTimerBase<Duration>::DEFAULT_TICK_INTERVAL =
+    detail::HHWheelTimerDurationConst<Duration>::DEFAULT_TICK_INTERVAL;
 
 template <class Duration>
 HHWheelTimerBase<Duration>::Callback::Callback() {}

folly/io/async/HHWheelTimer.h

@@ -31,6 +31,21 @@
 
 namespace folly {
 
+namespace detail {
+template <class Duration>
+struct HHWheelTimerDurationConst;
+
+template <>
+struct HHWheelTimerDurationConst<std::chrono::milliseconds> {
+  static constexpr int DEFAULT_TICK_INTERVAL = 10;
+};
+
+template <>
+struct HHWheelTimerDurationConst<std::chrono::microseconds> {
+  static constexpr int DEFAULT_TICK_INTERVAL = 200;
+};
+} // namespace detail
+
 /**
  * Hashed Hierarchical Wheel Timer
  *
@@ -343,6 +358,7 @@ class HHWheelTimerBase : private folly::AsyncTimeout,
   }
 };
 
+// std::chrono::milliseconds
 using HHWheelTimer = HHWheelTimerBase<std::chrono::milliseconds>;
 extern template class HHWheelTimerBase<std::chrono::milliseconds>;