From d823d6fa703cbe97c4d16e3d61d8767d565cb627 Mon Sep 17 00:00:00 2001
From: Jeff Becker <jeff@i2p.rocks>
Date: Thu, 28 Nov 2019 16:12:46 -0500
Subject: [PATCH] only flush when no other jobs are executing

---
 llarp/path/transit_hop.cpp | 82 +++++++++++++++++---------------------
 llarp/path/transit_hop.hpp |  2 +
 2 files changed, 38 insertions(+), 46 deletions(-)

diff --git a/llarp/path/transit_hop.cpp b/llarp/path/transit_hop.cpp
index fd1b370d9..9d493ccd2 100644
--- a/llarp/path/transit_hop.cpp
+++ b/llarp/path/transit_hop.cpp
@@ -36,6 +36,8 @@ namespace llarp
     {
       m_UpstreamGather.enable();
       m_DownstreamGather.enable();
+      m_UpstreamWorkCounter   = 0;
+      m_DownstreamWorkCounter = 0;
     }
 
     bool
@@ -122,6 +124,18 @@ namespace llarp
     void
     TransitHop::DownstreamWork(TrafficQueue_ptr msgs, AbstractRouter* r)
     {
+      m_DownstreamWorkCounter++;
+      auto flushIt = [self = shared_from_this(), r]() {
+        std::vector< RelayDownstreamMessage > msgs;
+        do
+        {
+          auto maybe = self->m_DownstreamGather.tryPopFront();
+          if(not maybe.has_value())
+            break;
+          msgs.emplace_back(maybe.value());
+        } while(true);
+        self->HandleAllDownstream(std::move(msgs), r);
+      };
       for(auto& ev : *msgs)
       {
         RelayDownstreamMessage msg;
@@ -132,27 +146,32 @@ namespace llarp
         msg.X = buf;
         llarp::LogDebug("relay ", msg.X.size(), " bytes downstream from ",
                         info.upstream, " to ", info.downstream);
-        if(m_DownstreamGather.empty() || m_DownstreamGather.full())
+        if(m_DownstreamGather.full())
         {
-          LogicCall(r->logic(), [self = shared_from_this(), r]() {
-            std::vector< RelayDownstreamMessage > msgs;
-            do
-            {
-              auto maybe = self->m_DownstreamGather.tryPopFront();
-              if(not maybe.has_value())
-                break;
-              msgs.emplace_back(maybe.value());
-            } while(true);
-            self->HandleAllDownstream(std::move(msgs), r);
-          });
+          LogicCall(r->logic(), flushIt);
         }
         m_DownstreamGather.pushBack(msg);
       }
+      m_DownstreamWorkCounter--;
+      if(m_DownstreamWorkCounter == 0)
+        flushIt();
     }
 
     void
     TransitHop::UpstreamWork(TrafficQueue_ptr msgs, AbstractRouter* r)
     {
+      m_UpstreamWorkCounter++;
+      auto flushIt = [self = shared_from_this(), r]() {
+        std::vector< RelayUpstreamMessage > msgs;
+        do
+        {
+          auto maybe = self->m_UpstreamGather.tryPopFront();
+          if(not maybe.has_value())
+            break;
+          msgs.emplace_back(maybe.value());
+        } while(true);
+        self->HandleAllUpstream(std::move(msgs), r);
+      };
       for(auto& ev : *msgs)
       {
         const llarp_buffer_t buf(ev.first);
@@ -161,22 +180,15 @@ namespace llarp
         msg.pathid = info.txID;
         msg.Y      = ev.second ^ nonceXOR;
         msg.X      = buf;
-        if(m_UpstreamGather.empty() || m_UpstreamGather.full())
+        if(m_UpstreamGather.full())
         {
-          LogicCall(r->logic(), [self = shared_from_this(), r]() {
-            std::vector< RelayUpstreamMessage > msgs;
-            do
-            {
-              auto maybe = self->m_UpstreamGather.tryPopFront();
-              if(not maybe.has_value())
-                break;
-              msgs.emplace_back(maybe.value());
-            } while(true);
-            self->HandleAllUpstream(std::move(msgs), r);
-          });
+          LogicCall(r->logic(), flushIt);
         }
         m_UpstreamGather.pushBack(msg);
       }
+      m_UpstreamWorkCounter--;
+      if(m_UpstreamWorkCounter == 0)
+        flushIt();
     }
 
     void
@@ -235,17 +247,6 @@ namespace llarp
                                           std::move(m_UpstreamQueue), r));
 
       m_UpstreamQueue = nullptr;
-      std::vector< RelayUpstreamMessage > msgs;
-      do
-      {
-        auto maybe = m_UpstreamGather.tryPopFront();
-        if(not maybe.has_value())
-          break;
-        msgs.emplace_back(maybe.value());
-      } while(true);
-      if(msgs.empty())
-        return;
-      HandleAllUpstream(std::move(msgs), r);
     }
 
     void
@@ -256,17 +257,6 @@ namespace llarp
                                           shared_from_this(),
                                           std::move(m_DownstreamQueue), r));
       m_DownstreamQueue = nullptr;
-      std::vector< RelayDownstreamMessage > msgs;
-      do
-      {
-        auto maybe = m_DownstreamGather.tryPopFront();
-        if(not maybe.has_value())
-          break;
-        msgs.emplace_back(maybe.value());
-      } while(true);
-      if(msgs.empty())
-        return;
-      HandleAllDownstream(std::move(msgs), r);
     }
 
     bool
diff --git a/llarp/path/transit_hop.hpp b/llarp/path/transit_hop.hpp
index 3e9648526..1627bb24c 100644
--- a/llarp/path/transit_hop.hpp
+++ b/llarp/path/transit_hop.hpp
@@ -235,6 +235,8 @@ namespace llarp
           m_FlushOthers;
       thread::Queue< RelayUpstreamMessage > m_UpstreamGather;
       thread::Queue< RelayDownstreamMessage > m_DownstreamGather;
+      std::atomic< uint32_t > m_UpstreamWorkCounter;
+      std::atomic< uint32_t > m_DownstreamWorkCounter;
     };
 
     inline std::ostream&