From 32065b5a38dcad1a7c30d89509ee9be02ad5373d Mon Sep 17 00:00:00 2001
From: Henning Baldersheim <balder@yahoo-inc.com>
Date: Mon, 30 Nov 2020 11:21:19 +0000
Subject: Simplify and use a single events_before_wakup number in the transport
 thread for controlling wakeup frequency.

---
 fnet/src/vespa/fnet/transport.cpp        |  2 +-
 fnet/src/vespa/fnet/transport.h          |  8 ++++----
 fnet/src/vespa/fnet/transport_thread.cpp | 16 ++++------------
 3 files changed, 9 insertions(+), 17 deletions(-)

(limited to 'fnet/src')

diff --git a/fnet/src/vespa/fnet/transport.cpp b/fnet/src/vespa/fnet/transport.cpp
index 445eed20ce4..e59186069ce 100644
--- a/fnet/src/vespa/fnet/transport.cpp
+++ b/fnet/src/vespa/fnet/transport.cpp
@@ -30,7 +30,7 @@ FNET_Transport::FNET_Transport(vespalib::AsyncResolver::SP resolver, vespalib::C
       _crypto_engine(std::move(crypto)),
       _work_pool(std::make_unique<vespalib::ThreadStackExecutor>(1, 128 * 1024, fnet_work_pool, 1024)),
       _threads(),
-      _optimizeFor(vespalib::Executor::OptimizeFor::LATENCY)
+      _events_before_wakeup(1)
 {
     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 45a2122c9c9..1126f68e69f 100644
--- a/fnet/src/vespa/fnet/transport.h
+++ b/fnet/src/vespa/fnet/transport.h
@@ -31,7 +31,7 @@ private:
     vespalib::CryptoEngine::SP _crypto_engine;
     std::unique_ptr<vespalib::SyncableThreadExecutor> _work_pool;
     Threads _threads;
-    vespalib::Executor::OptimizeFor _optimizeFor;
+    size_t  _events_before_wakeup;
 
 public:
     /**
@@ -53,9 +53,9 @@ 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;
+    size_t events_before_wakeup() const { return _events_before_wakeup; }
+    void events_before_wakeup(size_t events_before_wakeup_in) {
+        _events_before_wakeup = events_before_wakeup_in;
     }
 
     /**
diff --git a/fnet/src/vespa/fnet/transport_thread.cpp b/fnet/src/vespa/fnet/transport_thread.cpp
index 82c2353092f..1200d2ad6f9 100644
--- a/fnet/src/vespa/fnet/transport_thread.cpp
+++ b/fnet/src/vespa/fnet/transport_thread.cpp
@@ -22,8 +22,6 @@ using OptimizeFor = vespalib::Executor::OptimizeFor;
 
 namespace {
 
-constexpr size_t WAKEUP_LIMIT_IN_ADAPTIVE_MODE = 100;
-
 struct Sync : public FNET_IExecutable
 {
     vespalib::Gate gate;
@@ -32,11 +30,6 @@ struct Sync : public FNET_IExecutable
     }
 };
 
-bool needWakeup(vespalib::Executor::OptimizeFor mode, size_t qLen) {
-    return ((mode == OptimizeFor::LATENCY) && (qLen == 1)) ||
-           ((mode == OptimizeFor::ADAPTIVE) && (qLen == WAKEUP_LIMIT_IN_ADAPTIVE_MODE));
-}
-
 } // namespace<unnamed>
 
 void
@@ -132,7 +125,7 @@ FNET_TransportThread::PostEvent(FNET_ControlPacket *cpacket,
         _queue.QueuePacket_NoLock(cpacket, context);
         qLen = _queue.GetPacketCnt_NoLock();
     }
-    if (needWakeup(_owner.optimizeFor(), qLen)) {
+    if (qLen == _owner.events_before_wakeup()) {
         _selector.wakeup();
     }
     return true;
@@ -488,11 +481,10 @@ FNET_TransportThread::EventLoopIteration()
         // sample current time (performed once per event loop iteration)
         _now = clock::now();
 
-        // handle wakeup and io-events
+        // handle io-events
         _selector.dispatch(*this);
-        if (owner().optimizeFor() != vespalib::Executor::OptimizeFor::LATENCY) {
-            handle_wakeup();
-        }
+
+        handle_wakeup();
 
         // handle IOC time-outs
         if (_config._iocTimeOut > 0) {
-- 
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