epoll ET LT性能测试

最新推荐文章于 2025-06-21 15:45:09 发布

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最新推荐文章于 2025-06-21 15:45:09 发布 · 886 阅读

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通过对epoll的ET（边沿触发）和LT（水平触发）模式进行性能测试，得出结论：在实际应用中，LT模式表现与ET模式相近，甚至稍优。测试主要关注epoll句柄在缓冲区变化时的状态处理方式。

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结论

总体来看两者差距不大，甚至LT比ET还稍微好一点。两者区别：epoll的句柄是否对缓冲区的变化进行状态变化。

绑定的单核cpu 16GB内存 centos 7.0 gcc 版本 4.8.5 
使用taskset绑定为单核，ab压测
taskset -cp 6 10714
ab -n 50000 -k 127.0.0.1/

ET:
Requests per second:    4974.68 [#/sec] (mean)
Time per request:       0.201 [ms] (mean)
Time per request:       0.201 [ms] (mean, across all concurrent requests)

Requests per second:    5013.28 [#/sec] (mean)
Time per request:       0.199 [ms] (mean)
Time per request:       0.199 [ms] (mean, across all concurrent requests)

LT:
Requests per second:    5104.07 [#/sec] (mean)
Time per request:       0.196 [ms] (mean)
Time per request:       0.196 [ms] (mean, across all concurrent requests)

Requests per second:    5024.95 [#/sec] (mean)
Time per request:       0.199 [ms] (mean)
Time per request:       0.199 [ms] (mean, across all concurrent requests)

代码

1 LT代码

/*
 * 编译：g++ -o epoll-lt epoll-lt.cpp
 * 运行： ./epoll-lt
 * 测试：curl -v localhost
 */
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/socket.h>
#include <unistd.h>
#include <map>
#include <string>
using namespace std;

bool output_log = true;

#define exit_if(r, ...)                                                                          \
    if (r) {                                                                                     \
        printf(__VA_ARGS__);                                                                     \
        printf("%s:%d error no: %d error msg %s\n", __FILE__, __LINE__, errno, strerror(errno)); \
        exit(1);                                                                                 \
    }

void setNonBlock(int fd) {
    int flags = fcntl(fd, F_GETFL, 0);
    exit_if(flags < 0, "fcntl failed");
    int r = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
    exit_if(r < 0, "fcntl failed");
}

void updateEvents(int efd, int fd, int events, int op) {
    struct epoll_event ev;
    memset(&ev, 0, sizeof(ev));
    ev.events = events;
    ev.data.fd = fd;
    printf("%s fd %d events read %d write %d\n", op == EPOLL_CTL_MOD ? "mod" : "add", fd, ev.events & EPOLLIN, ev.events & EPOLLOUT);
    int r = epoll_ctl(efd, op, fd, &ev);
    exit_if(r, "epoll_ctl failed");
}

void handleAccept(int efd, int fd) {
    struct sockaddr_in raddr;
    socklen_t rsz = sizeof(raddr);
    i