io_uring笔记

io_uring 异步

要求内核linux 5.10
异步四元组：1、init（create）2、commit 3、callback 4、destory
fio : 测iops一秒钟读写磁盘的次数

方式	磁盘iops
io_uring	11.6k
libaio	10.7k
psync	5k
spdk(内存操作 , 尽可能都放到用户态)	157k

io_uring 使用

io_uring内核api：
io uring. setup();
io uring register();
io_ uring_ enter();

liburing接口：

io_uring. _queue. init. params
io_uring_prep_accept
io_ uring. prep_recv
io_uring_prep_send(uring, )
io_ uring_submit0;
io_uring wait_cqe
io_uring_ peek_ batch_ cqe
io_uring_cq_advance//取消事件

在这里插入图片描述
猜测运行机制：

io _uring. _setup();
做两件事
1）注册两个队列
2）使用mmap映射内核的队列和用户态的队列：

echo_websever:

// io_uring, tcp server// multhread, select/poll, epoll, coroutine, iouring
// reactor// io #include <liburing.h>#include <stdio.h>
#include <string.h>#include <sys/socket.h>
#include <netinet/in.h>#include <unistd.h>#define ENTRIES_LENGTH		4096enum {READ,WRITE,ACCEPT,};struct conninfo {int connfd;int type;
};void set_read_event(struct io_uring *ring, int fd, void *buf, size_t len, int flags) {struct io_uring_sqe *sqe = io_uring_get_sqe(ring);io_uring_prep_recv(sqe, fd, buf, len, flags);struct conninfo ci = {.connfd = fd,.type = READ};memcpy(&sqe->user_data, &ci, sizeof(struct conninfo));}void set_write_event(struct io_uring *ring, int fd, const void *buf, size_t len, int flags) {struct io_uring_sqe *sqe = io_uring_get_sqe(ring);io_uring_prep_send(sqe, fd, buf, len, flags);struct conninfo ci = {.connfd = fd,.type = WRITE};memcpy(&sqe->user_data, &ci, sizeof(struct conninfo));}void set_accept_event(struct io_uring *ring, int fd,struct sockaddr *cliaddr, socklen_t *clilen, unsigned flags) {struct io_uring_sqe *sqe = io_uring_get_sqe(ring);io_uring_prep_accept(sqe, fd, cliaddr, clilen, flags);struct conninfo ci = {.connfd = fd,.type = ACCEPT};memcpy(&sqe->user_data, &ci, sizeof(struct conninfo));}int main() {int listenfd = socket(AF_INET, SOCK_STREAM, 0);  // if (listenfd == -1) return -1;
// listenfdstruct sockaddr_in servaddr, clientaddr;servaddr.sin_family = AF_INET;servaddr.sin_addr.s_addr = htonl(INADDR_ANY);servaddr.sin_port = htons(9999);if (-1 == bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr))) {return -2;}listen(listenfd, 10);struct io_uring_params params;memset(&params, 0, sizeof(params));// epoll --> struct io_uring ring;io_uring_queue_init_params(ENTRIES_LENGTH, &ring, &params);socklen_t clilen = sizeof(clientaddr);set_accept_event(&ring, listenfd, (struct sockaddr*)&clientaddr, &clilen, 0);char buffer[1024] = {0};
//while (1) {struct io_uring_cqe *cqe;//从sqe地址复制地址io_uring_submit(&ring) ; //提交，在这个阶段进行accpet和recv、write等int ret = io_uring_wait_cqe(&ring, &cqe); //回调struct io_uring_cqe *cqes[10];int cqecount = io_uring_peek_batch_cqe(&ring, cqes, 10);// 10是每次最多返回10个队列元素int i = 0;unsigned count = 0;for (i = 0;i < cqecount;i ++) {cqe = cqes[i];count ++;struct conninfo ci;memcpy(&ci, &cqe->user_data, sizeof(ci));if (ci.type == ACCEPT) {int connfd = cqe->res;set_read_event(&ring, connfd, buffer, 1024, 0);} else if (ci.type == READ) {int bytes_read = cqe->res;if (bytes_read == 0) {close(ci.connfd);} else if (bytes_read < 0) {} else {printf("buffer : %s\n", buffer);set_write_event(&ring, ci.connfd, buffer, bytes_read, 0);}} else if (ci.type == WRITE) {set_read_event(&ring, ci.connfd, buffer, 1024, 0);}}io_uring_cq_advance(&ring, count);}}