能跑的epoll

#include <sys/types.h> 
#include <sys/stat.h> 
#include <sys/time.h> 
#include <sys/socket.h> 
#include <sys/signal.h> 
#include <sys/resource.h> 
#include <fcntl.h> 
#include <stdlib.h> 
#include <stdio.h> 
#include <string.h> 
#include <unistd.h> 
#include <errno.h> 

#include <sys/epoll.h> 


#define RUNTIMES 16 


static int count, writes, fired; 
static int *pipes; 
static int num_pipes, num_active, num_writes; 
static int epfd; 
static struct epoll_event *events; 



unsigned long long getustime(void) { 
   struct timeval tm; 

   gettimeofday(&tm, NULL); 
   return (unsigned long long) tm.tv_sec * 1000000ULL + (unsigned long long) tm.tv_usec; 
} 


void read_cb(int fd, int idx) { 
   int widx = idx + num_active + 1; 
   u_char ch; 

   if (read(fd, &ch, sizeof(ch))) 
      count++; 
   else 
      fprintf(stderr, "false read event: fd=%d idx=%d\n", fd, idx); 
   if (writes) { 
      if (widx >= num_pipes) 
         widx -= num_pipes; 
      write(pipes[2 * widx + 1], "e", 1); 
      writes--; 
      fired++; 
   } 
} 


int run_once(long *work, unsigned long long *tr) { 
   int i, res; 
   unsigned long long ts, te; 

   fired = 0; 
   for (i = 0; i < num_active; i++, fired++) 
      write(pipes[i * 2 + 1], "e", 1); 

   count = 0; 
   writes = num_writes; 

   ts = getustime(); 
   do { 
      res = epoll_wait(epfd, events, num_pipes, 0); 
      for (i = 0; i < res; i++) 
         read_cb(pipes[2 * events[i].data.u32], events[i].data.u32); 
   } while (count != fired); 
   te = getustime(); 

   *tr = te - ts; 
   *work = count; 

   return (0); 
} 


int main (int argc, char **argv) { 
   struct rlimit rl; 
   int i, c; 
   long work; 
   unsigned long long tr; 
   int *cp; 
   struct epoll_event ev; 
   extern char *optarg; 

   num_pipes = 100; 
   num_active = 1; 
   num_writes = num_pipes; 
   while ((c = getopt(argc, argv, "n:a:w:")) != -1) { 
      switch (c) { 
      case 'n': 
         num_pipes = atoi(optarg); 
         break; 
      case 'a': 
         num_active = atoi(optarg); 
         break; 
      case 'w': 
         num_writes = atoi(optarg); 
         break; 
      default: 
         fprintf(stderr, "Illegal argument \"%c\"\n", c); 
         exit(1); 
      } 
   } 

   rl.rlim_cur = rl.rlim_max = num_pipes * 2 + 50; 
   if (setrlimit(RLIMIT_NOFILE, &rl) == -1) { 
      perror("setrlimit"); 
      exit(1); 
   } 

   events = calloc(num_pipes, sizeof(struct epoll_event)); 
   pipes = calloc(num_pipes * 2, sizeof(int)); 
   if (events == NULL || pipes == NULL) { 
      perror("malloc"); 
      exit(1); 
   } 

   if ((epfd = epoll_create(num_pipes)) == -1) { 
      perror("epoll_create"); 
      exit(1); 
   } 

   for (cp = pipes, i = 0; i < num_pipes; i++, cp += 2) { 
      if (pipe(cp) == -1) { 
         perror("pipe"); 
         exit(1); 
      } 
      fcntl(cp[0], F_SETFL, fcntl(cp[0], F_GETFL) | O_NONBLOCK); 
   } 

   for (cp = pipes, i = 0; i < num_pipes; i++, cp += 2) { 
      ev.events = EPOLLIN; 
      ev.data.u32 = i; 
      if (epoll_ctl(epfd, EPOLL_CTL_ADD, cp[0], &ev) < 0) { 
         perror("epoll_ctl"); 
         exit(1); 
      } 
   } 

   for (i = 0; i < RUNTIMES; i++) { 
      run_once(&work, &tr); 
      if (!work) 
         exit(1); 
      fprintf(stdout, "%lf\n", (double) tr / (double) work); 
   } 

   exit(0); 
}