epoll 边界触发模式1,2的实现
本篇贴出在上篇文章中介绍的模式1的实现代码.
首先,因为是多线程的程序,必须防止某一资源在一个线程中使用的时候,却在另一个线程中释放了.
其中最主要的便是socket_t结构,为了杜绝这个问题,对应用层来说,应该根本不知道socket_t的存在,
仅仅提供一个HANDLE给应用层就足够了.
#ifndef _KENDYNET_H #define _KENDYNET_H #include "MsgQueue.h" typedef struct list_node { struct list_node *next; }list_node; #define LIST_NODE list_node node; /*IO请求和完成队列使用的结构*/ typedef struct { LIST_NODE; struct iovec *iovec; int iovec_count; int bytes_transfer; int error_code; }st_io; enum { //完成模式,当套接口从不可读/写变为激活态时, 如果有IO请求,则完成请求,并将完成通告发送给工作线程 MODE_COMPLETE = 0, //poll模式,当套接口从不可读/写变为激活态时, 如果有IO请求,将请求发送给工作线程,由工作线程完成请求 MODE_POLL, }; //初始化网络系统 int InitNetSystem(); typedef int HANDLE; struct block_queue; struct block_queue* CreateEventQ(); void DestroyEventQ(struct block_queue**); HANDLE CreateEngine(char); void CloseEngine(HANDLE); int EngineRun(HANDLE); int Bind2Engine(HANDLE,HANDLE); //获取和投递事件到engine的队列中 //int GetQueueEvent(HANDLE,struct block_queue*,st_io **,int timeout); int GetQueueEvent(HANDLE,MsgQueue_t,st_io **,int timeout); int PutQueueEvent(HANDLE,st_io *); /* * 发送和接收,如果操作立即完成返回完成的字节数 * 否则返回0,当IO异步完成后会通告到事件队列中. * 返回-1表示套接口出错或断开 * notify:当IO立即可完成时,是否向事件队 * 列提交一个完成通告,设置为1会提交,0为不提交. */ int WSASend(HANDLE,st_io*,int notify); int WSARecv(HANDLE,st_io*,int notify); #endif
这里定义的st_io结构,相当与IOCP里的OVERLAPPED结构,其中,第一个成员是list_node,这样
可以很方便的将st_io放在队列中.
然后是GetQueueEvent函数,这个函数的作用相当于IOCP里的GetCompleteStatus,用于从队列
中获取事件,不同的是,这个队列是由用户提供的,也就是参数中的block_queue*,如果调用
GetQueueEvent的时候,engine的buffering_event_queue中没有事件,就会将block_queue
放到一个等待队列中(block_thread_queue),当其它地方调用PutQueueEvent的时候,首先
会看下是否有线程在等待,有就把它的block_queue弹出push一个事件进去,然后唤醒阻塞
的线程.
#include "KendyNet.h" #include "Engine.h" #include "Socket.h" #include "link_list.h" #include "HandleMgr.h" #include <assert.h> #include "MsgQueue.h" int InitNetSystem() { return InitHandleMgr(); } struct block_queue* CreateEventQ() { return BLOCK_QUEUE_CREATE(); } void DestroyEventQ(struct block_queue** eq) { BLOCK_QUEUE_DESTROY(eq); } int EngineRun(HANDLE engine) { engine_t e = GetEngineByHandle(engine); if(!e) return -1; e->Loop(e); return 0; } HANDLE CreateEngine(char mode) { HANDLE engine = NewEngine(); if(engine >= 0) { engine_t e = GetEngineByHandle(engine); e->mode = mode; LIST_CLEAR(e->buffering_event_queue); LIST_CLEAR(e->block_thread_queue); if(0 != e->Init(e)) { CloseEngine(engine); engine = -1; } } return engine; } void CloseEngine(HANDLE handle) { ReleaseEngine(handle); } int Bind2Engine(HANDLE e,HANDLE s) { engine_t engine = GetEngineByHandle(e); socket_t sock = GetSocketByHandle(s); if(!engine || ! sock) return -1; if(engine->Register(engine,sock) == 0) { sock->engine = engine; return 0; } return -1; } //int GetQueueEvent(HANDLE handle, struct block_queue *EventQ,st_io **io ,int timeout) int GetQueueEvent(HANDLE handle, MsgQueue_t EventQ,st_io **io ,int timeout) { assert(EventQ);assert(io); /* engine_t e = GetEngineByHandle(handle); if(!e) return -1; spin_lock(e->mtx,0);//mutex_lock(e->mtx); if(e->status == 0) { spin_unlock(e->mtx);//mutex_unlock(e->mtx); return -1; } if(*io = LIST_POP(st_io*,e->buffering_event_queue)) { spin_unlock(e->mtx);//mutex_unlock(e->mtx); return 0; } //插入到等待队列中，阻塞 LIST_PUSH_FRONT(e->block_thread_queue,EventQ); spin_unlock(e->mtx);//mutex_unlock(e->mtx); if(POP_FORCE_WAKE_UP == BLOCK_QUEUE_POP(EventQ,io,timeout)) return -1;//因为engine的释放而被强制唤醒 */ engine_t e = GetEngineByHandle(handle); if(!e) return -1; mutex_lock(e->mtx); if(e->status == 0) { mutex_unlock(e->mtx); return -1; } if(*io = LIST_POP(st_io*,e->buffering_event_queue)) { mutex_unlock(e->mtx); return 0; } //插入到等待队列中，阻塞 LIST_PUSH_FRONT(e->block_thread_queue,EventQ); mutex_unlock(e->mtx); GetMsg(EventQ,io,sizeof(*io),0); if(*io == 0) return -1; return 0; } int PutQueueEvent(HANDLE handle,st_io *io) { assert(io); engine_t e = GetEngineByHandle(handle); if(!e) return -1; return put_event(e,io); } extern int put_event(engine_t e,st_io *io); int WSASend(HANDLE sock,st_io *io,int notify) { assert(io); socket_t s = GetSocketByHandle(sock); if(!s) return -1; int active_send_count = -1; int ret = 0; mutex_lock(s->send_mtx); //为保证执行顺序与请求的顺序一致,先将请求插入队列尾部,再弹出队列首元素 LIST_PUSH_BACK(s->pending_send,io); io = 0; if(s->writeable) { io = LIST_POP(st_io*,s->pending_send); active_send_count = s->active_write_count; } mutex_unlock(s->send_mtx); if(s->engine->mode == MODE_POLL) { if(io) { //当前处于激活态 if(notify) //不直接处理,将处理交给完成线程 put_event(s->engine,io); else ret = _send(s,io,active_send_count,notify); } } else { if(io) ret = _send(s,io,active_send_count,notify); } return ret; } int WSARecv(HANDLE sock,st_io *io,int notify) { assert(io); socket_t s = GetSocketByHandle(sock); if(!s) return -1; int active_recv_count = -1; int ret = 0; mutex_lock(s->recv_mtx); //为保证执行顺序与请求的顺序一致,先将请求插入队列尾部,再弹出队列首元素 LIST_PUSH_BACK(s->pending_recv,io); io = 0; if(s->readable) { io = LIST_POP(st_io*,s->pending_recv); active_recv_count = s->active_read_count; } mutex_unlock(s->recv_mtx); if(s->engine->mode == MODE_POLL) { if(io) { //当前处于激活态 if(notify) //不直接处理,将处理交给完成线程 put_event(s->engine,io); else ret = _recv(s,io,active_recv_count,notify); } } else { if(io) ret = _recv(s,io,active_recv_count,notify); } return ret; }
然后是engine接口:
#ifndef _ENGINE_H #define _ENGINE_H #include "sync.h" //#include "thread.h" #include "link_list.h" struct socket_wrapper; typedef struct engine { int (*Init)(struct engine*); void (*Loop)(struct engine*); int (*Register)(struct engine*,struct socket_wrapper*); int (*UnRegister)(struct engine*,struct socket_wrapper*); mutex_t mtx; volatile int status; /*0:关闭状态,1:开启状态*/ int poller_fd; //完成事件相关成员 struct link_list *buffering_event_queue; //当没有线程等待时，事件将被缓存到这个队列中 struct link_list *block_thread_queue; //正在等待完成消息的线程 //thread_t engine_thread; //运行engine的线程 }*engine_t; engine_t create_engine(); void free_engine(engine_t *); void stop_engine(engine_t); #endif
engine接口提供了4个函数指针,可根据不同的系统实现相应的函数,在这里使用的是linux的epoll.
#include "Engine.h" #include "link_list.h" #include "KendyNet.h" #include <stdlib.h> #include "epoll.h" #include <assert.h> engine_t create_engine() { engine_t e = malloc(sizeof(*e)); if(e) { e->mtx = mutex_create(); e->status = 0; e->buffering_event_queue = LIST_CREATE(); e->block_thread_queue = LIST_CREATE(); e->Init = epoll_init; e->Loop = epoll_loop; e->Register = epoll_register; e->UnRegister = epoll_unregister; //e->engine_thread = 0; } return e; } void free_engine(engine_t *e) { assert(e); assert(*e); mutex_destroy(&(*e)->mtx); LIST_DESTROY(&(*e)->buffering_event_queue); LIST_DESTROY(&(*e)->block_thread_queue); //if((*e)->engine_thread) // destroy_thread(&(*e)->engine_thread); free(*e); *e = 0; } int put_event(engine_t e,st_io *io) { mutex_lock(e->mtx); struct block_queue *EventQ = LIST_POP(struct block_queue*,e->block_thread_queue); if(!EventQ) { //没有等待的线程，先缓冲事件 LIST_PUSH_BACK(e->buffering_event_queue,io); io = 0; } mutex_unlock(e->mtx); if(io) BLOCK_QUEUE_PUSH(EventQ,io); return 0; } void stop_engine(engine_t e) { mutex_lock(e->mtx); e->status = 0; //join(e->engine_thread); //强制唤醒所有等待在完成队列上的线程 struct block_queue *queue = 0; /*唤醒所有等待在完成队列的线程*/ while(queue = LIST_POP(struct block_queue *,e->block_thread_queue)) { BLOCK_QUEUE_FORCE_WAKEUP(queue); } mutex_unlock(e->mtx); }
epoll的实现：
#include "epoll.h" #include "Socket.h" #include "SocketWrapper.h" #include "HandleMgr.h" int epoll_init(engine_t e); { e->poller_fd = TEMP_FAILURE_RETRY(epoll_create(MAX_SOCKET)); return e->poller_fd > 0 ? 0:-1; } int epoll_register(engine_t e, socket_t s) { int ret = -1; struct epoll_event ev; ev.data.ptr = s; ev.events = EV_IN | EV_OUT | EV_ET; TEMP_FAILURE_RETRY(ret = epoll_ctl(e->poller_fd,EPOLL_CTL_ADD,s->fd,&ev)); return ret; } inline int epoll_unregister(engine_t e,socket_t s) { struct epoll_event ev;int ret; TEMP_FAILURE_RETRY(ret = epoll_ctl(s->poller_fd,EPOLL_CTL_DEL,s->fd,&ev)); return ret; } void epoll_loop(engine_t n) { struct epoll_event events[MAX_SOCKET]; memset(events,0,sizeof(events)); while(1) { int nfds = TEMP_FAILURE_RETRY(epoll_wait(n->poller_fd,events,MAX_SOCKET,-1)); if(nfds < 0) { break; } int i; for(i = 0 ; i < nfds ; ++i) { socket_t sock = (socket_t)events[i].data.ptr; if(sock) { //套接口可读 if(events[i].events & EPOLLIN) { on_read_active(sock); } //套接口可写 if(events[i].events & EPOLLOUT) { on_write_active(sock); } if(events[i].events & EPOLLERR) { //套接口异常 } } } } }
最后是socket_t
#ifndef _SOCKETWRAPPER_H #define _SOCKETWRAPPER_H #include "Engine.h" typedef struct socket_wrapper { mutex_t mtx;//保证ReleaseSocketWrapper只会被正常执行一次 volatile int status;//0:未开启;1:正常; engine_t *engine; volatile int readable; volatile int writeable; volatile int active_read_count; volatile int active_write_count; int fd; //当发送/接收无法立即完成时,把请求投入下面两个队列中, //当套接口可读/可写时再完成请求 struct link_list *pending_send;//尚未处理的发请求 struct link_list *pending_recv;//尚未处理的读请求 mutex_t recv_mtx; mutex_t send_mtx; }*socket_t; void on_read_active(socket_t); void on_write_active(socket_t); socket_t create_socket(); void free_socket(socket_t*); int _recv(socket_t,st_io*,int,int notify); int _send(socket_t,st_io*,int,int notify); #endif
socket_t.c
#include "Socket.h" #include <assert.h> #include <stdlib.h> #include <errno.h> #include "SocketWrapper.h" #include "KendyNet.h" socket_t create_socket() { socket_t s = malloc(sizeof(*s)); if(s) { s->mtx = mutex_create(); s->recv_mtx = mutex_create(); s->send_mtx = mutex_create(); s->pending_send = LIST_CREATE(); s->pending_recv = LIST_CREATE(); s->status = 0; s->engine = 0; } return s; } void free_socket(socket_t *s) { assert(s);assert(*s); mutex_destroy(&(*s)->mtx); mutex_destroy(&(*s)->recv_mtx); mutex_destroy(&(*s)->send_mtx); destroy_list(&(*s)->pending_send); destroy_list(&(*s)->pending_recv); free(*s); *s = 0; } void on_read_active(socket_t s) { assert(s); mutex_lock(s->recv_mtx); s->readable = 1; int active_recv_count = ++s->active_read_count; st_io *req = LIST_POP(st_io*,s->pending_recv); mutex_unlock(s->recv_mtx); if(req) { if(s->engine->mode == MODE_COMPLETE) _recv(s,req,active_recv_count,1); else put_event(s->engine,req); } } void on_write_active(socket_t s) { assert(s); mutex_lock(s->send_mtx); s->writeable = 1; int active_send_count = ++s->active_write_count; st_io *req = LIST_POP(st_io*,s->pending_send); mutex_unlock(s->send_mtx); if(req) { if(s->engine->mode == MODE_COMPLETE) _send(s,req,active_send_count,1); else put_event(s->engine,req); } } int _recv(socket_t s,st_io* io_req,int active_recv_count,int notify) { assert(s);assert(io_req); while(1) { int retry = 0; int bytes_transfer = io_req->bytes_transfer = TEMP_FAILURE_RETRY(readv(s->fd,io_req->iovec,io_req->iovec_count)); io_req->error_code = 0; if(bytes_transfer < 0) { switch(errno) { case EAGAIN: { mutex_lock(s->recv_mtx); if(active_recv_count != s->active_read_count) { active_recv_count = s->active_read_count; retry = 1; } else { s->readable = 0; LIST_PUSH_FRONT(s->pending_recv,io_req); } mutex_unlock(s->recv_mtx); if(retry) continue; return 0; } break; default://连接出错 { io_req->error_code = errno; } break; } } else if(bytes_transfer == 0) bytes_transfer = -1; if(notify) put_event(s->engine,io_req); return bytes_transfer; } } int _send(socket_t s,st_io* io_req,int active_send_count,int notify) { assert(s);assert(io_req); while(1) { int retry = 0; int bytes_transfer = io_req->bytes_transfer = TEMP_FAILURE_RETRY(writev(s->fd,io_req->iovec,io_req->iovec_count)); io_req->error_code = 0; if(bytes_transfer < 0) { switch(errno) { case EAGAIN: { mutex_lock(s->send_mtx); if(active_send_count != s->active_write_count) { active_send_count = s->active_write_count; retry = 1; } else { s->writeable = 0; //将请求重新放回到队列 LIST_PUSH_FRONT(s->pending_send,io_req); } mutex_unlock(s->send_mtx); if(retry) continue; return 0; } break; default://连接出错 { io_req->error_code = errno; } break; } } else if(bytes_transfer == 0) bytes_transfer = -1; if(notify) put_event(s->engine,io_req); return bytes_transfer; } }
用户提供的完成例程代码大概如下:
st_io *io = 0; block_queue *EventQ; while(GetQueueEvent(engine,EventQ,&io ,0) == 0) { if(io) { HANDLE sock = GetHandle(io); OnRecv(io); int ret; //发起新的读,直到套接字变为不可读 while((ret = WSARecv(sock,io,0)) > 0) { OnRecv(io); } if(ret < 0) { //连接断开 CloseSocket(sock); } } }
对于快速的发送方，完成例程接收完并处理之后，套接口上可能马上又有数据可读了，这样在epoll线程中执行recv的机会比较小。
但如果发送方全都是慢速的，例如每一秒发送一次，则会导致几乎所有的recv操作都在epoll线程中执行，当连接数巨大时没法发挥
多核处理器的优势，所以就有了模型2,epoll线程完全不处理recv,当套接字变为激活时，将请求投递到队列中，交给complete例程
去执行recv.
(2012.4.16修改,增加对模型2的支持，CreateEngine时可选择传入参数MODE_COMPLETE或MODE_POLL,
当传入MODE_POLL时，GetQueueEvent返回的事件表明套接口可读/写，且有读/写请求,传入MODE_COMPLETE
GetQueueEvent返回的事件表明一个读/写请求已经完成)
测试程序如下,注意IORoutinePoll和IORoutine的区别:
test.c
#include <stdio.h> #include <stdlib.h> #include "KendyNet.h" #include "thread.h" #include "SocketWrapper.h" #include "atomic.h" enum { RECV_FINISH = 0, SEND_FINISH, }; typedef struct IoContext { st_io m_ioStruct; unsigned char m_opType; void *ud; }IoContext; typedef struct _Socket { char send_buf[64]; char recv_buf[64]; struct iovec recv_iovec; struct iovec send_iovec; IoContext m_IORecvComp; IoContext m_IOSendComp; HANDLE m_sock; }_Socket; HANDLE engine; const char *ip; long port; void *ListerRoutine(void *arg) { thread_t thread = (thread_t)CUSTOM_ARG(arg); struct sockaddr_in servaddr; HANDLE listerfd; if((listerfd = Tcp_Listen(ip,port,&servaddr,5)) == 0) { while(!is_terminate(thread)) { struct sockaddr sa; socklen_t salen; HANDLE sock = Accept(listerfd,&sa,&salen); if(sock >= 0) { setNonblock(sock); _Socket *_sock = malloc(sizeof(*_sock)); _sock->m_sock = sock; _sock->m_IORecvComp.m_opType = RECV_FINISH; _sock->m_IOSendComp.m_opType = SEND_FINISH; _sock->m_IORecvComp.ud = _sock->m_IOSendComp.ud = _sock; _sock->recv_iovec.iov_base = _sock->recv_buf; _sock->send_iovec.iov_base = _sock->send_buf; _sock->m_IORecvComp.m_ioStruct.iovec = &_sock->recv_iovec; _sock->m_IOSendComp.m_ioStruct.iovec = &_sock->send_iovec; _sock->m_IOSendComp.m_ioStruct.iovec_count = _sock->m_IORecvComp.m_ioStruct.iovec_count = 1; //printf("接到一个连接\n"); if(0 != Bind2Engine(engine,sock)) { printf("bind出错\n"); CloseSocket(sock); free(_sock); } else { //发起第一个读请求 _sock->m_IORecvComp.m_ioStruct.iovec->iov_len = 64; WSARecv(sock,(st_io*)&(_sock->m_IORecvComp),1); } } else { printf("accept出错\n"); } } printf("listener 终止\n"); } return 0; } //COMPLETE MODE void *IORoutine(void *arg) { st_io* ioComp; //struct block_queue *EventQ = CreateEventQ(); MsgQueue_t EventQ = CreateMsgQ(); while(1) { ioComp = 0; if(0 > GetQueueEvent(engine,EventQ,&ioComp,-1)) { printf("poller终止\n"); break; } //printf("唤醒咯\n"); if(ioComp) { if(ioComp->bytes_transfer <= 0) { //printf("套接口断开\n"); _Socket *sock = (_Socket*)(((IoContext*)ioComp)->ud); //连接关闭 CloseSocket(sock->m_sock); free(sock); } else { IoContext *context = (IoContext*)ioComp; _Socket *sock = (_Socket*)context->ud; if(context->m_opType == RECV_FINISH) { int byteTransfer = 0; //把数据回发给客户端 memcpy(sock->send_buf,sock->recv_buf,ioComp->bytes_transfer); sock->m_IOSendComp.m_ioStruct.iovec->iov_len = ioComp->bytes_transfer; WSASend(sock->m_sock,(st_io*)&(sock->m_IOSendComp),0); //继续读 while((byteTransfer = WSARecv(sock->m_sock,(st_io*)context,0)) > 0) { memcpy(sock->send_buf,sock->recv_buf,byteTransfer); sock->m_IOSendComp.m_ioStruct.iovec->iov_len = byteTransfer; byteTransfer = WSASend(sock->m_sock,(st_io*)&(sock->m_IOSendComp),0); if(byteTransfer == 0) printf("can't write\n"); if(byteTransfer < 0) { printf("close\n"); break; } } if(byteTransfer < 0) { //printf("套接口断开\n"); CloseSocket(sock->m_sock); free(sock); } } } } } printf("IO end\n"); //DestroyEventQ(&EventQ); DestroyMsgQ(&EventQ); return 0; } //POLL MODE void *IORoutinePoll(void *arg) { st_io* ioComp; MsgQueue_t EventQ = CreateMsgQ(); while(1) { ioComp = 0; if(0 > GetQueueEvent(engine,EventQ,&ioComp,-1)) { printf("poller终止\n"); break; } if(ioComp) { IoContext *context = (IoContext*)ioComp; _Socket *sock = (_Socket*)context->ud; if(context->m_opType == RECV_FINISH) { int byteTransfer = 0; while((byteTransfer = WSARecv(sock->m_sock,(st_io*)context,0)) > 0) { memcpy(sock->send_buf,sock->recv_buf,byteTransfer); sock->m_IOSendComp.m_ioStruct.iovec->iov_len = byteTransfer; byteTransfer = WSASend(sock->m_sock,(st_io*)&(sock->m_IOSendComp),0); if(byteTransfer == 0) printf("can't write1\n"); if(byteTransfer < 0) { printf("close\n"); break; } } if(byteTransfer < 0) { //printf("connection close\n"); CloseSocket(sock->m_sock); free(sock); } } else WSASend(sock->m_sock,(st_io*)&(sock->m_IOSendComp),0); } } printf("IO end\n"); DestroyMsgQ(&EventQ); return 0; } void *EngineRoutine(void *arg) { EngineRun(engine); printf("Engine stop\n"); return 0; } int main(int argc,char **argv) { ip = "127.0.0.1";//argv[]; port = atoi(argv[1]); signal(SIGPIPE,SIG_IGN); if(InitNetSystem() != 0) { printf("Init error\n"); return 0; } //engine = CreateEngine(MODE_POLL); engine = CreateEngine(MODE_COMPLETE); thread_t listener = create_thread(0); start_run(listener,ListerRoutine,listener); int complete_count = atoi(argv[2]); int i = 0; for( ; i < complete_count; ++i) { thread_t complete_t = create_thread(0); //start_run(complete_t,IORoutinePoll,0); start_run(complete_t,IORoutine,0); } thread_t engine_thread = create_thread(1); start_run(engine_thread,EngineRoutine,0); getchar(); CloseEngine(engine); join(engine_thread); return 0; }
