我目前正在编写一个应用程序(使用 boost),它将有一个生产者抓取帧和一个消费者阅读帧。我在生产者中添加了一个睡眠语句来模拟抓取帧的时间。我希望消费者等待条件变量,并在生产者的第一次通知被唤醒以读取帧。但是,我在日志文件中看到的是消费者(主线程)在条件变量上等待,但是在消费者退出等待读取帧之前,生产者经历了几次通知。
这是我的 Worker.h
class Worker {
static log4cxx::LoggerPtr m_log;
public:
Worker();
virtual ~Worker();
void start();
void stop();
void getCurrentFrame(/*cv::Mat& frame*/);
private:
void processFrames();
volatile bool m_stopRequested;
bool m_bFrameReady;
boost::mutex m_mutex;
boost::condition_variable condF;
boost::shared_ptr<boost::thread> m_thread;
};
工人.cpp
LoggerPtr Worker::m_log(Logger::getLogger("fdx.Worker"));
Worker::Worker() {
m_bFrameReady = false;
LOG4CXX_INFO(m_log, "Worker() c-tor");
m_stopRequested = false;
}
Worker::~Worker() {
LOG4CXX_INFO(m_log, "Worker() d-tor");
}
void Worker::start()
{
LOG4CXX_INFO(m_log, "Worker()::start()");
assert(!m_thread);
m_thread = boost::shared_ptr<boost::thread>(new boost::thread(&Worker::processFrames, this));
LOG4CXX_WARN(m_log, "Worker()::start() thread[" << m_thread->get_id() << "] started!");
}
void Worker::stop()
{
LOG4CXX_INFO(m_log, "Worker()::stop()");
if(m_thread != NULL)
{
LOG4CXX_INFO(m_log, "Worker()::stop() ThrId [" << m_thread->get_id() << "]");
m_stopRequested = true;
m_thread->join();
}
else
{
LOG4CXX_WARN(m_log, "Worker()::stop() The thread for this camera was never started.");
}
LOG4CXX_INFO(m_log, "Worker()::stop() thread stopped!");
}
void Worker::processFrames()
{
LOG4CXX_WARN(m_log, "Worker()::processFrames() Thread[" << boost::this_thread::get_id() << "] starting...");
int rc = 0;
std::stringstream ss;
while(!this->m_stopRequested)
{
boost::mutex::scoped_lock lock(m_mutex);
LOG4CXX_WARN(m_log, "Worker()::processFrames() Got a Write lock");
m_bFrameReady = true;
LOG4CXX_WARN(m_log, "Worker()::processFrames() Frame ready set to true");
boost::this_thread::sleep(boost::posix_time::milliseconds(200));
LOG4CXX_WARN(m_log, "Worker()::processFrames() Write Un-lock");
lock.unlock();
LOG4CXX_WARN(m_log, "Worker()::processFrames() Notify");
condF.notify_one();
}
}
void Worker::getCurrentFrame()
{
boost::mutex::scoped_lock lock(m_mutex);
while(!this->m_bFrameReady)
{
LOG4CXX_WARN(m_log, "Worker::getCurrentFrame() wait for Read lock");
condF.wait(lock);
}
LOG4CXX_WARN(m_log, "Worker::getCurrentFrame() Frame ready; Got a Read lock");
m_bFrameReady = false;
LOG4CXX_WARN(m_log, "Worker::getCurrentFrame() Frame ready set to false");
LOG4CXX_WARN(m_log, "Worker::getCurrentFrame() Read Un-lock");
lock.unlock();
}
主文件
LoggerPtr logger(Logger::getLogger("TCamApp"));
int main(int argc, char** argv)
{
int rc = 0;
char cwDir[FILENAME_MAX];
Worker* pWorker = NULL;
memset(cwDir, 0, sizeof(cwDir));
getcwd(cwDir, FILENAME_MAX);
std::cout << "Current Working Dir[" << cwDir << "]" << endl;
std::stringstream ss;
ss << "" << cwDir << "/logs.properties";
std::cout << "logs.properties file[" << ss.str() << "]" << endl;
struct stat st;
if(!stat(ss.str().c_str(), &st))
{
PropertyConfigurator::configure(ss.str());
}
else
{
BasicConfigurator::configure();
}
LOG4CXX_INFO(logger, "Application [" << argv[0] << "] starting...");
pWorker = new Worker();
assert(pWorker);
pWorker->start();
for(int i = 0; i < 100; i++)
{
pWorker->getCurrentFrame();
LOG4CXX_INFO(logger, "Iteration [" << i << "]");
//boost::this_thread::sleep(boost::posix_time::milliseconds(20));
}
pWorker->stop();
LOG4CXX_INFO(logger, "Application [" << argv[0] << "] stopping...");
return rc;
}
以下是我的日志文件的摘录:
2012-07-11 15:33:53,943 [0x7f5707bcf780] INFO TCamApp - Application [/home/op/workspace/TestThreads/Debug/TestThreads] starting...
2012-07-11 15:33:53,944 [0x7f5707bcf780] WARN fdx.Worker - Worker()::start() thread[0x15e4c50] started!
2012-07-11 15:33:53,944 [0x7f5707bcf780] WARN fdx.Worker - Worker::getCurrentFrame() wait for Read lock
2012-07-11 15:33:53,944 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Thread[0x15e4c50] starting...
2012-07-11 15:33:53,944 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Got a Write lock
2012-07-11 15:33:53,944 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Frame ready set to true
2012-07-11 15:33:54,145 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Write Un-lock
2012-07-11 15:33:54,145 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Notify
2012-07-11 15:33:54,145 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Got a Write lock
2012-07-11 15:33:54,145 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Frame ready set to true
2012-07-11 15:33:54,345 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Write Un-lock
2012-07-11 15:33:54,345 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Notify
2012-07-11 15:33:54,345 [0x7f5707bcf780] WARN fdx.Worker - Worker::getCurrentFrame() Frame ready; Got a Read lock
2012-07-11 15:33:54,345 [0x7f5707bcf780] WARN fdx.Worker - Worker::getCurrentFrame() Frame ready set to false
2012-07-11 15:33:54,345 [0x7f5707bcf780] WARN fdx.Worker - Worker::getCurrentFrame() Read Un-lock
2012-07-11 15:33:54,346 [0x7f5707bcf780] INFO TCamApp - Iteration [0]
2012-07-11 15:33:54,346 [0x7f5707bcf780] WARN fdx.Worker - Worker::getCurrentFrame() wait for Read lock
2012-07-11 15:33:54,346 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Got a Write lock
2012-07-11 15:33:54,346 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Frame ready set to true
2012-07-11 15:33:54,546 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Write Un-lock
2012-07-11 15:33:54,547 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Notify
2012-07-11 15:33:54,547 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Got a Write lock
2012-07-11 15:33:54,547 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Frame ready set to true
2012-07-11 15:33:54,747 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Write Un-lock
2012-07-11 15:33:54,747 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Notify
2012-07-11 15:33:54,747 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Got a Write lock
2012-07-11 15:33:54,747 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Frame ready set to true
2012-07-11 15:33:54,948 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Write Un-lock
2012-07-11 15:33:54,948 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Notify
2012-07-11 15:33:54,948 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Got a Write lock
2012-07-11 15:33:54,948 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Frame ready set to true
2012-07-11 15:33:55,148 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Write Un-lock
2012-07-11 15:33:55,149 [0x7f57059c1700] WARN fdx.Worker - Worker()::processFrames() Notify
2012-07-11 15:33:55,149 [0x7f5707bcf780] WARN fdx.Worker - Worker::getCurrentFrame() Frame ready; Got a Read lock
2012-07-11 15:33:55,149 [0x7f5707bcf780] WARN fdx.Worker - Worker::getCurrentFrame() Frame ready set to false
2012-07-11 15:33:55,149 [0x7f5707bcf780] WARN fdx.Worker - Worker::getCurrentFrame() Read Un-lock
2012-07-11 15:33:55,149 [0x7f5707bcf780] INFO TCamApp - Iteration [1]
从日志中可以看出,主线程等待读取,但另一个线程会在主线程退出它的 wait() 之前产生多个通知。
我研究了一些并认为我已经正确编码了它,但它的行为不像我预期的那样。我将不胜感激有关解决方案的任何建议。谢谢。