如何在自己的线程上运行时钟

我试图在c++中创建一个步骤测序器，最终将发送MIDI数据。我通过在它自己的线程上有一个时钟来创建它，该线程计算自上一个节拍以来的时间量，如果是下一个节拍的时间，它就向控制台写入一段数据。

然而，我发现无论我将BPM设置为什么，我获得消息的速度都明显太慢。我似乎不明白为什么这个线程上的时间是错误的，而且我对std::chrono库的工作方式并不熟悉，这也没有帮助。想法吗?

#include <thread>
#include <mutex>
#include <chrono>
#include <vector>
#include <iostream>
class StepSequencer {
 public:
  StepSequencer();
  ~StepSequencer();
  void run();
  void setBeatsPerMinute(float bpm);
  void addNote(int noteValue, int beatIndex);
  void playNote(int beatIndex);
 protected:
  int mNumberOfBeatBins;
  int mSequencerPlayhead;
  float mBeatsPerMinute;
  float mSecondsPerBeat;
  std::vector<int> mBeatBins;
  std::mutex mMutex;
  std::thread mSequencerThread;
  bool mRunSequencerThread;
  std::chrono::time_point<std::chrono::system_clock> mLastBeatTime;
  std::chrono::time_point<std::chrono::system_clock> mCurrentTime;
};
#include "stdafx.h"
#include "StepSequencer.h"
StepSequencer::StepSequencer() {
  mNumberOfBeatBins = 16;
  for(int i = 0; i < 16; i++) {
    mBeatBins.push_back(0);
  }
  mBeatsPerMinute = 0;
  mSecondsPerBeat = 1;
  mLastBeatTime = std::chrono::system_clock::now();
  mCurrentTime = std::chrono::system_clock::now();
  mSequencerPlayhead = 0;
    mRunSequencerThread = false;
    mSequencerThread = std::thread(&StepSequencer::run, this);
}
StepSequencer::~StepSequencer() {
  if(mSequencerThread.joinable()) {
    mSequencerThread.join();
  }
}
void StepSequencer::run() {
  mRunSequencerThread = true;
  while(mRunSequencerThread) {
        mCurrentTime = std::chrono::system_clock::now();
    mMutex.lock();
        if (std::chrono::duration_cast<std::chrono::seconds>(mCurrentTime - mLastBeatTime).count() > mSecondsPerBeat) {
      mSequencerPlayhead++;
      mSequencerPlayhead = mSequencerPlayhead % mNumberOfBeatBins;
      playNote(mSequencerPlayhead);
            mLastBeatTime = std::chrono::system_clock::now();
    }
    mMutex.unlock();
    this_thread::sleep_for(std::chrono::milliseconds(1));
  }
} 
void StepSequencer::setBeatsPerMinute(float bpm) {
  mMutex.lock();
  mBeatsPerMinute = bpm;
  if(mBeatsPerMinute > 0) {
      mSecondsPerBeat = 60.0 / mBeatsPerMinute;
  }
  else {
    mSecondsPerBeat = 1;
  }
 mMutex.unlock();
}
void StepSequencer::addNote(int noteValue, int beatIndex) {
  mBeatBins[beatIndex] = noteValue;
}
void StepSequencer::playNote(int beatIndex) {
  std::cout << mBeatBins[beatIndex] << std::endl;
}