text: // @file dur_stats.h
  
  /**
  *    Copyright (C) 2012 10gen Inc.
  *
  *    This program is free software: you can redistribute it and/or  modify
  *    it under the terms of the GNU Affero General Public License, version 3,
  *    as published by the Free Software Foundation.
  *
  *    This program is distributed in the hope that it will be useful,
  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *    GNU Affero General Public License for more details.
  *
  *    You should have received a copy of the GNU Affero General Public License
  *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  *    As a special exception, the copyright holders give permission to link the
  *    code of portions of this program with the OpenSSL library under certain
  *    conditions as described in each individual source file and distribute
  *    linked combinations including the program with the OpenSSL library. You
  *    must comply with the GNU Affero General Public License in all respects for
  *    all of the code used other than as permitted herein. If you modify file(s)
  *    with this exception, you may extend this exception to your version of the
  *    file(s), but you are not obligated to do so. If you do not wish to do so,
  *    delete this exception statement from your version. If you delete this
  *    exception statement from all source files in the program, then also delete
  *    it in the license file.
  */
  
  #include "mongo/db/jsobj.h"
  
  namespace mongo {
  namespace dur {
  
  /** journaling stats.  the model here is that the commit thread is the only writer, and that reads
   * are uncommon (from a serverStatus command and such).  Thus, there should not be multicore chatter
   * overhead.
  */
  struct Stats {
      struct S {
          std::string _CSVHeader() const;
          std::string _asCSV() const;
  
          void _asObj(BSONObjBuilder* builder) const;
  
          void reset();
  
          uint64_t getCurrentDurationMillis() const {
              return ((curTimeMicros64() - _startTimeMicros) / 1000);
          }
  
  
          // Not reported. Internal use only.
          uint64_t _startTimeMicros;
  
          // Reported statistics
          unsigned _durationMillis;
  
          unsigned _commits;
          unsigned _commitsInWriteLock;
  
          uint64_t _journaledBytes;
          uint64_t _uncompressedBytes;
          uint64_t _writeToDataFilesBytes;
  
          uint64_t _prepLogBufferMicros;
          uint64_t _writeToJournalMicros;
          uint64_t _writeToDataFilesMicros;
          uint64_t _remapPrivateViewMicros;
          uint64_t _commitsMicros;
          uint64_t _commitsInWriteLockMicros;
      };
  
  
      Stats();
      void reset();
  
      BSONObj asObj() const;
  
      const S* curr() const {
          return &_stats[_currIdx];
      }
      S* curr() {
          return &_stats[_currIdx];
      }
  
  private:
      S _stats[5];
      unsigned _currIdx;
  };
  
  extern Stats stats;
  }
  }
  