pdns/mtasker.hh

   1 /*
   2     PowerDNS Versatile Database Driven Nameserver
   3     Copyright (C) 2002 - 2009  PowerDNS.COM BV
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License version 2
   7     as published by the Free Software Foundation
   8
   9     Additionally, the license of this program contains a special
  10     exception which allows to distribute the program in binary form when
  11     it is linked against OpenSSL.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  21 */
  22 #ifndef MTASKER_HH
  23 #define MTASKER_HH
  24 #include <stdint.h>
  25 #include <queue>
  26 #include <vector>
  27 #include <map>
  28 #include <time.h>
  29 #include <boost/multi_index_container.hpp>
  30 #include <boost/multi_index/ordered_index.hpp>
  31 #include <boost/multi_index/key_extractors.hpp>
  32 #include "namespaces.hh"
  33 #include "misc.hh"
  34 #include "mtasker_context.hh"
  35 #include <memory>
  36 #include <boost/function.hpp>
  37 using namespace ::boost::multi_index;
  38
  39 // #define MTASKERTIMING 1
  40
  41 struct KeyTag {};
  42
  43 //! The main MTasker class
  44 /** The main MTasker class. See the main page for more information.
  45     \tparam EventKey Type of the key with which events are to be identified. Defaults to int.
  46     \tparam EventVal Type of the content or value of an event. Defaults to int. Cannot be set to void.
  47     \note The EventKey needs to have an operator< defined because it is used as the key of an associative array
  48 */
  49
  50 template<class EventKey=int, class EventVal=int> class MTasker
  51 {
  52 private:
  53   pdns_ucontext_t d_kernel;
  54   std::queue<int> d_runQueue;
  55   std::queue<int> d_zombiesQueue;
  56
  57   struct ThreadInfo
  58   {
  59         std::shared_ptr<pdns_ucontext_t> context;
  60         boost::function<void(void)> start;
  61         char* startOfStack;
  62         char* highestStackSeen;
  63 #ifdef MTASKERTIMING
  64         CPUTime dt;
  65         unsigned int totTime;
  66 #endif
  67   };
  68
  69   typedef std::map<int, ThreadInfo> mthreads_t;
  70   mthreads_t d_threads;
  71   int d_tid;
  72   int d_maxtid;
  73   size_t d_stacksize;
  74
  75   EventVal d_waitval;
  76   enum waitstatusenum {Error=-1,TimeOut=0,Answer} d_waitstatus;
  77
  78 public:
  79   struct Waiter
  80   {
  81     EventKey key;
  82     std::shared_ptr<pdns_ucontext_t> context;
  83     struct timeval ttd;
  84     int tid;
  85   };
  86
  87   typedef multi_index_container<
  88     Waiter,
  89     indexed_by <
  90                 ordered_unique<member<Waiter,EventKey,&Waiter::key> >,
  91                 ordered_non_unique<tag<KeyTag>, member<Waiter,struct timeval,&Waiter::ttd> >
  92                >
  93   > waiters_t;
  94
  95   waiters_t d_waiters;
  96
  97   //! Constructor
  98   /** Constructor with a small default stacksize. If any of your threads exceeds this stack, your application will crash.
  99       This limit applies solely to the stack, the heap is not limited in any way. If threads need to allocate a lot of data,
 100       the use of new/delete is suggested.
 101    */
 102   MTasker(size_t stacksize=8192) : d_tid(0), d_maxtid(0), d_stacksize(stacksize), d_waitstatus(Error)
 103   {
 104   }
 105
 106   typedef void tfunc_t(void *); //!< type of the pointer that starts a thread
 107   int waitEvent(EventKey &key, EventVal *val=0, unsigned int timeoutMsec=0, struct timeval* now=0);
 108   void yield();
 109   int sendEvent(const EventKey& key, const EventVal* val=0);
 110   void getEvents(std::vector<EventKey>& events);
 111   void makeThread(tfunc_t *start, void* val);
 112   bool schedule(struct timeval* now=0);
 113   bool noProcesses();
 114   unsigned int numProcesses();
 115   int getTid();
 116   unsigned int getMaxStackUsage();
 117   unsigned int getUsec();
 118
 119 private:
 120   EventKey d_eventkey;   // for waitEvent, contains exact key it was awoken for
 121 };
 122 #include "mtasker.cc"
 123
 124 #endif // MTASKER_HH
 125