Allow to optimize for throughput over latency. Wakeup is extremely expensive.

3 files changed, 12 insertions, 2 deletions

diff --git a/fnet/src/vespa/fnet/transport.cpp b/fnet/src/vespa/fnet/transport.cpp
index 8543d648400..445eed20ce4 100644
--- a/fnet/src/vespa/fnet/transport.cpp
+++ b/fnet/src/vespa/fnet/transport.cpp
@@ -29,7 +29,8 @@ FNET_Transport::FNET_Transport(vespalib::AsyncResolver::SP resolver, vespalib::C
     : _async_resolver(std::move(resolver)),
       _crypto_engine(std::move(crypto)),
       _work_pool(std::make_unique<vespalib::ThreadStackExecutor>(1, 128 * 1024, fnet_work_pool, 1024)),
-      _threads()
+      _threads(),
+      _optimizeFor(vespalib::Executor::OptimizeFor::LATENCY)
 {
     assert(num_threads >= 1);
     for (size_t i = 0; i < num_threads; ++i) {
diff --git a/fnet/src/vespa/fnet/transport.h b/fnet/src/vespa/fnet/transport.h
index 29f1fb2144f..45a2122c9c9 100644
--- a/fnet/src/vespa/fnet/transport.h
+++ b/fnet/src/vespa/fnet/transport.h
@@ -31,6 +31,7 @@ private:
     vespalib::CryptoEngine::SP _crypto_engine;
     std::unique_ptr<vespalib::SyncableThreadExecutor> _work_pool;
     Threads _threads;
+    vespalib::Executor::OptimizeFor _optimizeFor;
 
 public:
     /**
@@ -52,6 +53,11 @@ public:
         : FNET_Transport(vespalib::AsyncResolver::get_shared(), vespalib::CryptoEngine::get_default(), 1) {}
     ~FNET_Transport();
 
+    vespalib::Executor::OptimizeFor optimizeFor() const { return _optimizeFor; }
+    void optimizeFor(vespalib::Executor::OptimizeFor optimizeFor_in) {
+        _optimizeFor = optimizeFor_in;
+    }
+
     /**
      * Try to execute the given task on the internal work pool
      * executor (post). If the executor has been closed or there is
diff --git a/fnet/src/vespa/fnet/transport_thread.cpp b/fnet/src/vespa/fnet/transport_thread.cpp
index ba9c4bb7789..2064554392c 100644
--- a/fnet/src/vespa/fnet/transport_thread.cpp
+++ b/fnet/src/vespa/fnet/transport_thread.cpp
@@ -121,7 +121,7 @@ FNET_TransportThread::PostEvent(FNET_ControlPacket *cpacket,
             SafeDiscardEvent(cpacket, context);
             return false;
         }
-        wasEmpty = _queue.IsEmpty_NoLock();
+        wasEmpty = _queue.IsEmpty_NoLock() && _owner.optimizeFor() == vespalib::Executor::OptimizeFor::LATENCY;
         _queue.QueuePacket_NoLock(cpacket, context);
     }
     if (wasEmpty) {
@@ -482,6 +482,9 @@ FNET_TransportThread::EventLoopIteration()
 
         // handle wakeup and io-events
         _selector.dispatch(*this);
+        if (owner().optimizeFor() != vespalib::Executor::OptimizeFor::LATENCY) {
+            handle_wakeup();
+        }
 
         // handle IOC time-outs
         if (_config._iocTimeOut > 0) {