什么更快，pipe | fifo

Question

What is faster in linux : pipe or fifo ? Theoretical pipe is faster but how can i check this with a C program? I've tried to send a message between 2 procces , but the time from sending to receiving message is still 0 recklessly by lenght of message.

part of code :

struct timeval start,end;
char mesaj[100000]="";
for(i=0;i<99999;i++)
   strcat(mesaj,"d");
gettimeofday(&start,NULL);
if(fork()==0)
{
    write(fd,mesaj,strlen(mesaj));
    exit(0);
 }
 read(fd,mesaj,strlen(mesaj));
gettimeofday(&end,NULL);
long time=(end.tv_usec-start.tv_usec)/1000 + (end.tv_sce-start.tv_sec)*1000;
printf("Fifo time &lu\n",time);

Answer 1

A fifo shares the same implementation as a pipe in linux, so they're equally as fast.

The main difference in the two is how you create/open them.

If you want to measure it, you'll need to do work that's measurable. eg try to read/write 100MB of data (use a loop) . You also need to check for errors, since measuring how fast it takes to fail isn't what you want, and you need to check that you have actually read and written 100MB.

Answer 2

read() attempts to read up to count bytes from file descriptor fd into the buffer starting at buf.

this means that if you stay in the parent process you would read 0 bytes and just continue. you should notify to the parent that the reading has ended and busy wait on it. try to use signals or poll a file on the parent process and write 1 to it after the writing is done