granicus.if.org Git - icinga2/blob - lib/base/threadpool.hpp

   1 /******************************************************************************
   2  * Icinga 2                                                                   *
   3  * Copyright (C) 2012-2016 Icinga Development Team (https://www.icinga.org/)  *
   4  *                                                                            *
   5  * This program is free software; you can redistribute it and/or              *
   6  * modify it under the terms of the GNU General Public License                *
   7  * as published by the Free Software Foundation; either version 2             *
   8  * of the License, or (at your option) any later version.                     *
   9  *                                                                            *
  10  * This program is distributed in the hope that it will be useful,            *
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of             *
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
  13  * GNU General Public License for more details.                               *
  14  *                                                                            *
  15  * You should have received a copy of the GNU General Public License          *
  16  * along with this program; if not, write to the Free Software Foundation     *
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
  18  ******************************************************************************/
  19
  20 #ifndef THREADPOOL_H
  21 #define THREADPOOL_H
  22
  23 #include "base/i2-base.hpp"
  24 #include <boost/function.hpp>
  25 #include <boost/thread/thread.hpp>
  26 #include <boost/thread/mutex.hpp>
  27 #include <boost/thread/condition_variable.hpp>
  28 #include <deque>
  29
  30 namespace icinga
  31 {
  32
  33 #define QUEUECOUNT 4U
  34
  35 enum SchedulerPolicy
  36 {
  37         DefaultScheduler,
  38         LowLatencyScheduler
  39 };
  40
  41 /**
  42  * A thread pool.
  43  *
  44  * @ingroup base
  45  */
  46 class I2_BASE_API ThreadPool
  47 {
  48 public:
  49         typedef boost::function<void ()> WorkFunction;
  50
  51         ThreadPool(size_t max_threads = UINT_MAX);
  52         ~ThreadPool(void);
  53
  54         void Start(void);
  55         void Stop(void);
  56
  57         bool Post(const WorkFunction& callback, SchedulerPolicy policy = DefaultScheduler);
  58
  59 private:
  60         enum ThreadState
  61         {
  62                 ThreadUnspecified,
  63                 ThreadDead,
  64                 ThreadIdle,
  65                 ThreadBusy
  66         };
  67
  68         struct WorkItem
  69         {
  70                 WorkFunction Callback;
  71                 double Timestamp;
  72         };
  73
  74         struct Queue;
  75
  76         struct WorkerThread
  77         {
  78                 ThreadState State;
  79                 bool Zombie;
  80                 double Utilization;
  81                 double LastUpdate;
  82                 boost::thread *Thread;
  83
  84                 WorkerThread(ThreadState state = ThreadDead)
  85                         : State(state), Zombie(false), Utilization(0), LastUpdate(0), Thread(NULL)
  86                 { }
  87
  88                 void UpdateUtilization(ThreadState state = ThreadUnspecified);
  89
  90                 void ThreadProc(Queue& queue);
  91         };
  92
  93         struct Queue
  94         {
  95                 boost::mutex Mutex;
  96                 boost::condition_variable CV;
  97                 boost::condition_variable CVStarved;
  98
  99                 std::deque<WorkItem> Items;
 100
 101                 double WaitTime;
 102                 double ServiceTime;
 103                 int TaskCount;
 104
 105                 bool Stopped;
 106
 107                 WorkerThread Threads[16];
 108
 109                 Queue(void)
 110                         : WaitTime(0), ServiceTime(0), TaskCount(0), Stopped(false)
 111                 { }
 112
 113                 void SpawnWorker(boost::thread_group& group);
 114                 void KillWorker(boost::thread_group& group);
 115         };
 116
 117         int m_ID;
 118         static int m_NextID;
 119
 120         size_t m_MaxThreads;
 121
 122         boost::thread_group m_ThreadGroup;
 123
 124         boost::thread m_MgmtThread;
 125         boost::mutex m_MgmtMutex;
 126         boost::condition_variable m_MgmtCV;
 127         bool m_Stopped;
 128
 129         Queue m_Queues[QUEUECOUNT];
 130
 131         void ManagerThreadProc(void);
 132 };
 133
 134 }
 135
 136 #endif /* EVENTQUEUE_H */