commit a0dbfefbf3d09eebdc784f3fe6049c8bbc62a498
author David Reiss <dreiss@apache.org> Tue Mar 09 05:19:32 2010 +0000
committer David Reiss <dreiss@apache.org> Tue Mar 09 05:19:32 2010 +0000
tree 17f873e6cd020a1dfbccb319229341c731698050
parent b9db49c6776bde3b06ce8a5ceb32c873f8de4592

cpp: TNonBlockingServer: Use separate monitor for max queue

We were using the same monitor for max queue size and empty queue, this
meant the notifies might be going to the wrong place.

This change significantly reduces the time spent in futex calls in
loaded servers.

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@920667 13f79535-47bb-0310-9956-ffa450edef68

lib/cpp/src/concurrency/ThreadManager.cpp

diff --git a/lib/cpp/src/concurrency/ThreadManager.cpp b/lib/cpp/src/concurrency/ThreadManager.cpp
index 7bba0e6..52473c7 100644
--- a/lib/cpp/src/concurrency/ThreadManager.cpp
+++ b/lib/cpp/src/concurrency/ThreadManager.cpp
@@ -54,7 +54,9 @@
     workerMaxCount_(0),
     idleCount_(0),
     pendingTaskCountMax_(0),
-    state_(ThreadManager::UNINITIALIZED) {}
+    state_(ThreadManager::UNINITIALIZED),
+    monitor_(&mutex_),
+    maxMonitor_(&mutex_) {}
 
   ~Impl() { stop(); }
 
@@ -133,7 +135,9 @@
 
   friend class ThreadManager::Task;
   std::queue<shared_ptr<Task> > tasks_;
+  Mutex mutex_;
   Monitor monitor_;
+  Monitor maxMonitor_;
   Monitor workerMonitor_;
 
   friend class ThreadManager::Worker;
@@ -245,7 +249,7 @@
        * the manager will see it.
        */
       {
-        Synchronized s(manager_->monitor_);
+        Guard g(manager_->mutex_);
         active = isActive();
 
         while (active && manager_->tasks_.empty()) {
@@ -269,7 +273,7 @@
                thread that might be blocked on add. */
             if (manager_->pendingTaskCountMax_ != 0 &&
                 manager_->tasks_.size() == manager_->pendingTaskCountMax_ - 1) {
-              manager_->monitor_.notify();
+              manager_->maxMonitor_.notify();
             }
           }
         } else {
@@ -432,7 +436,7 @@
   }
 
   void ThreadManager::Impl::add(shared_ptr<Runnable> value, int64_t timeout) {
-    Synchronized s(monitor_);
+    Guard g(mutex_);
 
     if (state_ != ThreadManager::STARTED) {
       throw IllegalStateException();
@@ -441,7 +445,8 @@
     if (pendingTaskCountMax_ > 0 && (tasks_.size() >= pendingTaskCountMax_)) {
       if (canSleep() && timeout >= 0) {
         while (pendingTaskCountMax_ > 0 && tasks_.size() >= pendingTaskCountMax_) {
-          monitor_.wait(timeout);
+          // This is thread safe because the mutex is shared between monitors.
+          maxMonitor_.wait(timeout);
         }
       } else {
         throw TooManyPendingTasksException();