contention killer

llarp/ev/ev_libuv.cpp

@@ -10,7 +10,7 @@ namespace libuv
   /// call a function in logic thread via a handle
   template < typename Handle, typename Func >
   void
-  Call(Handle* h, Func&& f)
+  Call(Handle* h, Func f)
   {
     static_cast< Loop* >(h->loop->data)->Call(f);
   }
@@ -416,7 +416,7 @@ namespace libuv
     OnTick(uv_check_t* t)
     {
       ticker_glue* ticker = static_cast< ticker_glue* >(t->data);
-      Call(&ticker->m_Ticker, [ticker]() { ticker->func(); });
+      Call(t, ticker->func);
     }
 
     bool

llarp/router/outbound_message_handler.cpp

@@ -71,9 +71,12 @@ namespace llarp
   void
   OutboundMessageHandler::Tick()
   {
-    ProcessOutboundQueue();
-    RemoveEmptyPathQueues();
-    SendRoundRobin();
+    auto self = this;
+    m_Killer.TryAccess([self]() {
+      self->ProcessOutboundQueue();
+      self->RemoveEmptyPathQueues();
+      self->SendRoundRobin();
+    });
   }
 
   void
@@ -265,7 +268,9 @@ namespace llarp
   void
   OutboundMessageHandler::RemoveEmptyPathQueues()
   {
-    removedSomePaths = (not removedPaths.empty());
+    removedSomePaths = false;
+    if(removedPaths.empty())
+      return;
 
     while(not removedPaths.empty())
     {
@@ -275,6 +280,7 @@ namespace llarp
         outboundMessageQueues.erase(itr);
       }
     }
+    removedSomePaths = true;
   }
 
   void
@@ -282,7 +288,7 @@ namespace llarp
   {
     // send non-routing messages first priority
     auto &non_routing_mq = outboundMessageQueues[zeroID];
-    while(!non_routing_mq.empty())
+    while(not non_routing_mq.empty())
     {
       MessageQueueEntry entry = std::move(non_routing_mq.front());
       non_routing_mq.pop();

llarp/router/outbound_message_handler.hpp

@@ -123,6 +123,8 @@ namespace llarp
     ILinkManager *_linkManager;
     std::shared_ptr< Logic > _logic;
 
+    util::ContentionKiller m_Killer;
+
     // paths cannot have pathid "0", so it can be used as the "pathid"
     // for non-traffic (control) messages, so they can be prioritized.
     static const PathID_t zeroID;

llarp/util/thread/threading.cpp

@@ -53,5 +53,13 @@ namespace llarp
       (void)name;
 #endif
     }
+
+    void
+    ContentionKiller::TryAccess(std::function< void(void) > visit) const
+    {
+      NullLock lock(&__access);
+      visit();
+    }
+
   }  // namespace util
 }  // namespace llarp

llarp/util/thread/threading.hpp

@@ -156,6 +156,16 @@ namespace llarp
       return ::getpid();
 #endif
     }
+
+    // type for detecting contention on a resource
+    struct ContentionKiller
+    {
+      void
+      TryAccess(std::function< void(void) > visit) const;
+
+     private:
+      mutable NullMutex __access;
+    };
   }  // namespace util
 }  // namespace llarp