经过两个多月的攻关，终于搞定了live555多线程并稳定压测通过
2024.08.30：最新代码开源，地址：https://github.com/EasyDarwin/EasyRTSPServer
-----
live555已经发展了十几年了，不得不钦佩作者坚持不懈的奉献和国外的开源生态环境，live555可以说是大部分的安防从业者的入门之选，尤其是在嵌入式或者Linux系统上，其应用还是蛮广泛的，主要是其兼容性和稳定性；
但是随着live555十几年的不断迭代，很多开发者反复向作者Ross提到的多线程和IPv6的功能，作者也一直都没有去尝试，可能是这样会对live555的架构产生比较大的改动和影响，作者为了稳妥，选择了小改动、稳定、逐步迭代的方式, 虽然是性能稳定，但支持的路数有限，不能多线程工作始终是个坎; 网上找到几篇live555多线程的博客, 基本上大同小异，就是创建独立的UsageEnvironment和TaskSchedule, 由独立的线程分工协作; 本人也是这个思路,创建多个工作线程,每个工作线程内创建UsageEnvironment和TaskSchedule,然后各自开启EventLoop;
今天我们抛砖引玉，先大概聊一下主体思路，在后续的博客中将尽力完整地汇总这些思路和开发的过程：
目标
将live555修改为多线程, 每个通道对应一个工作线程,由工作线程对该通道进行独立处理;
大体修改点
修改支持多线程, 主要涉及到以下类的修改
- GenericMediaServer
- RTSPServer
GenericMediaServer.cpp
在GenericMediaServer的构造函数中, 创建工作线程个数,即最大支持的通道数;
GenericMediaServer
::GenericMediaServer(UsageEnvironment& env, int ourSocketV4, int ourSocketV6, Port ourPort,
unsigned reclamationSeconds)
: Medium(env),
fServerSocket4(ourSocketV4), fServerSocket6(ourSocketV6),
fServerPort(ourPort), fReclamationSeconds(reclamationSeconds),
fServerMediaSessions(HashTable::create(STRING_HASH_KEYS)),
fClientConnections(HashTable::create(ONE_WORD_HASH_KEYS)),
fClientSessions(HashTable::create(STRING_HASH_KEYS)) {
ignoreSigPipeOnSocket(fServerSocket4); // so that clients on the same host that are killed don't also kill us
ignoreSigPipeOnSocket(fServerSocket6); // so that clients on the same host that are killed don't also kill us
#ifdef LIVE_MULTI_THREAD_ENABLE
InitMutex(&mutexClientConnection);
memset(&multiThreadCore, 0x00, sizeof(MultiThread_CORE_T));
multiThreadCore.threadNum = MAX_DEFAULT_MULTI_THREAD_NUM;
multiThreadCore.threadTask = new LIVE_THREAD_TASK_T[multiThreadCore.threadNum];
memset(&multiThreadCore.threadTask[0], 0x00, sizeof(LIVE_THREAD_TASK_T) * multiThreadCore.threadNum);
for (int i=0; i<multiThreadCore.threadNum; i++)
{
char szName[36] = {0};
sprintf(szName, "worker thread %d", i);
multiThreadCore.threadTask[i].id = i;
multiThreadCore.threadTask[i].extPtr = this;
multiThreadCore.threadTask[i].pSubScheduler = BasicTaskScheduler::createNew();
multiThreadCore.threadTask[i].pSubEnv = BasicUsageEnvironment::createNew(*multiThreadCore.threadTask[i].pSubScheduler, i+1, szName);
CreateOSThread( &multiThreadCore.threadTask[i].osThread, __OSThread_Proc, (void *)&multiThreadCore.threadTask[i] );
}
#endif
// Arrange to handle connections from others:
env.taskScheduler().turnOnBackgroundReadHandling(fServerSocket4, incomingConnectionHandler4, this);
env.taskScheduler().turnOnBackgroundReadHandling(fServerSocket6, incomingConnectionHandler6, this);
}
接受客户端连接
按原有流程接受客户端连接;
分配客户端请求
在收到客户端发送的DESCRIBE命令后,
在通道列表中找出空闲的通道，将该客户端关联到该通道, 然后从主线程中移除该socket, 由工作线程接管该socket的操作;
后续有客户端如访问已经存在的通道,则主线程会将该请求直接分配给对应的工作线程处理;
注意: 主线程的工作到此结束，不要执行lookupServerMediaSession的操作;
在工作线程中, 接管客户端的socket后, 马上执行lookupServerMediaSession, 在该函数中，将后缀回调给上层调用程序, 由上层调用程序判断是否存在该通道，如不存在则返回失败，如存在则向前端取流，然后填充媒体信息返回成功, 库内部则创建相应的mediasession, 再回应客户端, 后续的则完成整个rtsp流程的交互;
注意: 创建MediaSession时，必须将工作线程中的UsageEnvironment传进去, 不能使用主线程中的envir();
int RTSPServer::RTSPClientConnection
::handleCmd_DESCRIBE(UsageEnvironment *pEnv, char const* urlPreSuffix, char const* urlSuffix, char const* fullRequestStr, LIVE_THREAD_TASK_T **pThreadTask)
{
int handleCmdRet = 0;
ServerMediaSession* session = NULL;
char* sdpDescription = NULL;
char* rtspURL = NULL;
do {
char urlTotalSuffix[2*RTSP_PARAM_STRING_MAX];
// enough space for urlPreSuffix/urlSuffix'\0'
urlTotalSuffix[0] = '\0';
if (urlPreSuffix[0] != '\0') {
strcat(urlTotalSuffix, urlPreSuffix);
strcat(urlTotalSuffix, "/");
}
strcat(urlTotalSuffix, urlSuffix);
if (!authenticationOK("DESCRIBE", urlTotalSuffix, fullRequestStr)) break;
// We should really check that the request contains an "Accept:" #####
// for "application/sdp", because that's what we're sending back #####
_TRACE(TRACE_LOG_DEBUG, "handleCmd_DESCRIBE socket[%d]\n", this->fOurSocket);
#ifdef LIVE_MULTI_THREAD_ENABLE
//如果当前是主线程,则进入到查找通道流程
if (pEnv->GetEnvirId() == 1000)
{
fOurServer.LockClientConnection(); //Lock
UsageEnvironment *pChEnv = fOurServer.GetEnvBySuffix(urlSuffix, this, pThreadTask);
if (NULL == pChEnv)
{
fOurServer.UnlockClientConnection(); //Unlock
handleCmdRet = -1;
this->assignSink = False;
this->pEnv = NULL;
handleCmd_notFound();
break;
}
else
{
_TRACE(TRACE_LOG_DEBUG, "将socket[%d] 关联到[%s]\n", this->fOurSocket, pChEnv->GetEnvirName());
//将socket从主线程移到工作线程中
UsageEnvironment *pMainEnv = &envir();
envir().taskScheduler().disableBackgroundHandling(fOurSocket);
fOurServer.UnlockClientConnection(); //Unlock
return 1000;
}
break;
}
#endif
// Begin by looking up the "ServerMediaSession" object for the specified "urlTotalSuffix":
//在工作线程中执行 lookupServerMediaSession
session = fOurServer.lookupServerMediaSession(pEnv, 1, this, urlTotalSuffix);
if (session == NULL) {
//pChEnv->taskScheduler().disableBackgroundHandling(fOurSocket);
_TRACE(TRACE_LOG_DEBUG, "socket[%d] 在[%s]中, 源未就绪[%s]\n", this->fOurSocket, pEnv->GetEnvirName(), urlTotalSuffix);
this->assignSink = False;
this->pEnv = NULL;
handleCmdRet = -1;
//envir().taskScheduler().disableBackgroundHandling(fOurSocket);
//fOurServer.ResetEnvBySuffix(urlSuffix, this);
handleCmd_notFound();
break;
}
session->incrementReferenceCount();
// Then, assemble a SDP description for this session:
sdpDescription = session->generateSDPDescription(fOurIPVer);
if (sdpDescription == NULL) {
// This usually means that a file name that was specified for a
// "ServerMediaSubsession" does not exist.
setRTSPResponse("404 File Not Found, Or In Incorrect Format");
break;
}
unsigned sdpDescriptionSize = strlen(sdpDescription);
// Also, generate our RTSP URL, for the "Content-Base:" header
// (which is necessary to ensure that the correct URL gets used in subsequent "SETUP" requests).
rtspURL = fOurRTSPServer.rtspURL(session, fOurIPVer, fClientInputSocket);
snprintf((char*)fResponseBuffer, sizeof fResponseBuffer,
"RTSP/1.0 200 OK\r\nCSeq: %s\r\n"
"%s"
"Content-Base: %s/\r\n"
"Content-Type: application/sdp\r\n"
"Content-Length: %d\r\n\r\n"
"%s",
fCurrentCSeq,
dateHeader(),
rtspURL,
sdpDescriptionSize,
sdpDescription);
} while (0);
if (session != NULL) {
// Decrement its reference count, now that we're done using it:
session->decrementReferenceCount();
if (session->referenceCount() == 0 && session->deleteWhenUnreferenced()) {
fOurServer.removeServerMediaSession(pEnv, session, True);
}
session->SetStreamStatus(1); //置标志,让后续访问该通道的客户端可以得到迅速响应
}
delete[] sdpDescription;
delete[] rtspURL;
return handleCmdRet;
}
历经2个多月，终于将多线程问题搞定. 在此记录一下, 欢迎探讨;
目前用户测试反馈的情况是：
- 连续压测8天时间；
- 接入摄像机30台；
- 客户端反复启动/停止播放；
- 内存、CPU、程序均非常稳定！
live555技术交流
邮件：289042893@qq.com
live555技术交流群：475947825
