From 1f97a239dcd77bd29e7d71bb47ac99e45e289814 Mon Sep 17 00:00:00 2001
From: Vinnie Falco <vinnie.falco@gmail.com>
Date: Tue, 22 Oct 2013 17:09:58 -0700
Subject: [PATCH] Measure CPU usage in Workers

---
 beast/chrono/CPUMeter.h               |  3 +-
 beast/threads/ServiceQueue.h          |  4 +-
 modules/beast_core/thread/Workers.cpp | 65 ++++++++++++++++-----------
 modules/beast_core/thread/Workers.h   |  4 ++
 4 files changed, 47 insertions(+), 29 deletions(-)

diff --git a/beast/chrono/CPUMeter.h b/beast/chrono/CPUMeter.h
index b78da25d7..5d21630a6 100644
--- a/beast/chrono/CPUMeter.h
+++ b/beast/chrono/CPUMeter.h
@@ -143,9 +143,10 @@ public:
     typedef ScopedTimeInterval <MeasureActive>  ScopedActiveTime;
 
     /** Returns the fraction of time that the CPU is being used. */
-    double getUtilizaton () const
+    double getUtilization () const
     {
         SharedState::ConstAccess state (m_state);
+
         double const seconds (state->usage.seconds());
         if (seconds > 0)
             return (state->usage.active.inSeconds() / seconds);
diff --git a/beast/threads/ServiceQueue.h b/beast/threads/ServiceQueue.h
index 2de4e44e0..715b6c52f 100644
--- a/beast/threads/ServiceQueue.h
+++ b/beast/threads/ServiceQueue.h
@@ -466,8 +466,8 @@ public:
     }
 
     /** Returns the percentage of time the queue is using the CPU. */
-    double getUtilizaton () const
-        { return m_cpuMeter.getUtilizaton(); }
+    double getUtilization () const
+        { return m_cpuMeter.getUtilization(); }
 
     /** Returns the allocator associated with the container. */
     allocator_type get_allocator() const
diff --git a/modules/beast_core/thread/Workers.cpp b/modules/beast_core/thread/Workers.cpp
index e856b06d3..576f58866 100644
--- a/modules/beast_core/thread/Workers.cpp
+++ b/modules/beast_core/thread/Workers.cpp
@@ -111,6 +111,11 @@ int Workers::numberOfCurrentlyRunningTasks () const noexcept
     return m_runningTaskCount.get ();
 }
 
+double Workers::getUtilization () const
+{
+    return m_usage.getUtilization();
+}
+
 void Workers::deleteWorkers (LockFreeStack <Worker>& stack)
 {
     for (;;)
@@ -157,36 +162,44 @@ void Workers::Worker::run ()
         {
             // Acquire a task or "internal task."
             //
-            m_workers.m_semaphore.wait ();
-
-            // See if there's a pause request. This
-            // counts as an "internal task."
-            //
-            int pauseCount = m_workers.m_pauseCount.get ();
-
-            if (pauseCount > 0)
             {
-                // Try to decrement
-                pauseCount = --m_workers.m_pauseCount;
+                CPUMeter::ScopedIdleTime elapsed (m_workers.m_usage);
 
-                if (pauseCount >= 0)
-                {
-                    // We got paused
-                    break;
-                }
-                else
-                {
-                    // Undo our decrement
-                    ++m_workers.m_pauseCount;
-                }
+                m_workers.m_semaphore.wait ();
             }
 
-            // We couldn't pause so we must have gotten
-            // unblocked in order to process a task.
-            //
-            ++m_workers.m_runningTaskCount;
-            m_workers.m_callback.processTask ();
-            --m_workers.m_runningTaskCount;
+            {
+                CPUMeter::ScopedActiveTime elapsed (m_workers.m_usage);
+
+                // See if there's a pause request. This
+                // counts as an "internal task."
+                //
+                int pauseCount = m_workers.m_pauseCount.get ();
+
+                if (pauseCount > 0)
+                {
+                    // Try to decrement
+                    pauseCount = --m_workers.m_pauseCount;
+
+                    if (pauseCount >= 0)
+                    {
+                        // We got paused
+                        break;
+                    }
+                    else
+                    {
+                        // Undo our decrement
+                        ++m_workers.m_pauseCount;
+                    }
+                }
+
+                // We couldn't pause so we must have gotten
+                // unblocked in order to process a task.
+                //
+                ++m_workers.m_runningTaskCount;
+                m_workers.m_callback.processTask ();
+                --m_workers.m_runningTaskCount;
+            }
 
             // Put the name back in case the callback changed it
             Thread::setCurrentThreadName (m_threadName);
diff --git a/modules/beast_core/thread/Workers.h b/modules/beast_core/thread/Workers.h
index 8c072f0a6..ba50b50de 100644
--- a/modules/beast_core/thread/Workers.h
+++ b/modules/beast_core/thread/Workers.h
@@ -93,6 +93,9 @@ public:
     */
     int numberOfCurrentlyRunningTasks () const noexcept;
 
+    /** Returns the fraction of time that the CPU is being used. */
+    double getUtilization () const;
+
     //--------------------------------------------------------------------------
 
 private:
@@ -129,6 +132,7 @@ private:
 
 private:
     Callback& m_callback;
+    CPUMeter m_usage;                            // CPU utilization across threads
     String m_threadNames;                        // The name to give each thread
     WaitableEvent m_allPaused;                   // signaled when all threads paused
     Semaphore m_semaphore;                       // each pending task is 1 resource