Only handle wakeup if necessary.

4 files changed, 17 insertions, 9 deletions

diff --git a/fnet/src/vespa/fnet/transport_thread.cpp b/fnet/src/vespa/fnet/transport_thread.cpp
index 8c3783c74a4..5e1a9759a60 100644
--- a/fnet/src/vespa/fnet/transport_thread.cpp
+++ b/fnet/src/vespa/fnet/transport_thread.cpp
@@ -393,7 +393,7 @@ FNET_TransportThread::InitEventLoop()
 }
 
 void
-FNET_TransportThread::handle_wakeup_events()
+FNET_TransportThread::handle_wakeup()
 {
     {
         std::lock_guard<std::mutex> guard(_lock);
@@ -473,10 +473,11 @@ FNET_TransportThread::EventLoopIteration() {
         _now = steady_clock::now();
 
         // handle io-events
-        _selector.dispatch(*this);
+        auto dispatchResult = _selector.dispatch(*this);
 
-        // Must be called after selector.dispatch
-        handle_wakeup_events();
+        if ((dispatchResult == vespalib::SelectorDispatchResult::NO_WAKEUP) && (getConfig()._events_before_wakeup > 1)) {
+            handle_wakeup();
+        }
 
         // handle IOC time-outs
         if (getConfig()._iocTimeOut > vespalib::duration::zero()) {
diff --git a/fnet/src/vespa/fnet/transport_thread.h b/fnet/src/vespa/fnet/transport_thread.h
index 36490c88656..517c0239887 100644
--- a/fnet/src/vespa/fnet/transport_thread.h
+++ b/fnet/src/vespa/fnet/transport_thread.h
@@ -172,8 +172,6 @@ private:
         return _shutdown.load(std::memory_order_relaxed);
     }
 
-    void handle_wakeup_events();
-
 public:
     FNET_TransportThread(const FNET_TransportThread &) = delete;
     FNET_TransportThread &operator=(const FNET_TransportThread &) = delete;
@@ -405,7 +403,7 @@ public:
 
 
     // Empty selector call-back for selector wakeup
-    void handle_wakeup() { }
+    void handle_wakeup();
 
     // selector call-back for io-events
     void handle_event(FNET_IOComponent &ctx, bool read, bool write);
diff --git a/vespalib/src/tests/net/selector/selector_test.cpp b/vespalib/src/tests/net/selector/selector_test.cpp
index 7d7a147bcb2..5c91dfdc122 100644
--- a/vespalib/src/tests/net/selector/selector_test.cpp
+++ b/vespalib/src/tests/net/selector/selector_test.cpp
@@ -77,7 +77,12 @@ struct Fixture {
     }
     Fixture &poll(int timeout_ms = 60000) {
         selector.poll(timeout_ms);
-        selector.dispatch(*this);
+        auto dispatchResult = selector.dispatch(*this);
+        if (wakeup) {
+            EXPECT_TRUE(dispatchResult == SelectorDispatchResult::WAKEUP_CALLED);
+        } else {
+            EXPECT_TRUE(dispatchResult == SelectorDispatchResult::NO_WAKEUP);
+        }
         return *this;
     }
     void verify(bool expect_wakeup, std::vector<std::pair<bool,bool> > expect_events) {
diff --git a/vespalib/src/vespa/vespalib/net/selector.h b/vespalib/src/vespa/vespalib/net/selector.h
index 6b1967ddcd9..24b3abc806e 100644
--- a/vespalib/src/vespa/vespalib/net/selector.h
+++ b/vespalib/src/vespa/vespalib/net/selector.h
@@ -31,6 +31,7 @@ public:
 };
 
 //-----------------------------------------------------------------------------
+enum class SelectorDispatchResult {WAKEUP_CALLED, NO_WAKEUP};
 
 template <typename Context>
 class Selector
@@ -55,11 +56,13 @@ public:
     void poll(int timeout_ms) { _events.extract(_epoll, timeout_ms); }
     size_t num_events() const { return _events.size(); }
     template <typename Handler>
-    void dispatch(Handler &handler) {
+    SelectorDispatchResult dispatch(Handler &handler) {
+        SelectorDispatchResult result = SelectorDispatchResult::NO_WAKEUP;
         for (const auto &evt: _events) {
             if (evt.data.ptr == nullptr) {
                 _wakeup_pipe.read_tokens();
                 handler.handle_wakeup();
+                result = SelectorDispatchResult::WAKEUP_CALLED;
             } else {
                 Context &ctx = *((Context *)(evt.data.ptr));
                 bool read = ((evt.events & (EPOLLIN  | EPOLLERR | EPOLLHUP)) != 0);
@@ -67,6 +70,7 @@ public:
                 handler.handle_event(ctx, read, write);
             }
         }
+        return result;
     }
 };