From fbe44761c0743bab0e270171218409213fd70f8d Mon Sep 17 00:00:00 2001
From: Alexander Block <ablock84@gmail.com>
Date: Fri, 12 Apr 2019 12:58:42 +0200
Subject: [PATCH] Don't wake up select if it was already woken up (#2863)

This avoids calling WakeupSelect() for each node instead of just once.
---
 src/net.cpp | 8 +++++---
 src/net.h   | 2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/net.cpp b/src/net.cpp
index 7f46d85d186e3..8b4b809f51d42 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -1321,10 +1321,10 @@ void CConnman::ThreadSocketHandler()
             }
         }
 
-        isInSelect = true;
+        wakeupSelectNeeded = true;
         int nSelect = select(have_fds ? hSocketMax + 1 : 0,
                              &fdsetRecv, &fdsetSend, &fdsetError, &timeout);
-        isInSelect = false;
+        wakeupSelectNeeded = false;
         if (interruptNet)
             return;
 
@@ -1521,6 +1521,8 @@ void CConnman::WakeSelect()
         LogPrint("net", "write to wakeupPipe failed\n");
     }
 #endif
+
+    wakeupSelectNeeded = false;
 }
 
 
@@ -3236,7 +3238,7 @@ void CConnman::PushMessage(CNode* pnode, CSerializedNetMsg&& msg, bool allowOpti
         if (optimisticSend == true)
             nBytesSent = SocketSendData(pnode);
         // wake up select() call in case there was no pending data before (so it was not selecting this socket for sending)
-        else if (!hasPendingData && isInSelect)
+        else if (!hasPendingData && wakeupSelectNeeded)
             WakeSelect();
     }
     if (nBytesSent)
diff --git a/src/net.h b/src/net.h
index a09b6b85052bf..4bf1a8206f59c 100644
--- a/src/net.h
+++ b/src/net.h
@@ -546,7 +546,7 @@ class CConnman
     /** a pipe which is added to select() calls to wakeup before the timeout */
     int wakeupPipe[2]{-1,-1};
 #endif
-    std::atomic<bool> isInSelect{false};
+    std::atomic<bool> wakeupSelectNeeded{false};
 
     std::thread threadDNSAddressSeed;
     std::thread threadSocketHandler;