bench pipe vs socket

bash.out

$ echo $((16*1024*1024)) | sudo tee /proc/sys/fs/pipe-max-size
$ gcc -ggdb3 -DN=256 -O1 bench-unixsocket-pipe.c
yura@falcon-new:~/tmp$ taskset -c 2,3 ./a.out 1000000000 $((16*1024*1024))                                                                                                                                                               
pipe lasts: 3.121495 sec, iter/sec: 320359349.183537
sock lasts: 5.402942 sec, iter/sec: 185084353.868363
pipe lasts: 3.287446 sec, iter/sec: 304187536.025462
sock lasts: 5.444722 sec, iter/sec: 183664098.170782
$ gcc -ggdb3 -DN=512 -O1 bench-unixsocket-pipe.c                                                                                                                                                                    
$ taskset -c 2,3 ./a.out 1000000000 $((16*1024*1024))
pipe lasts: 1.790609 sec, iter/sec: 558469073.197397
sock lasts: 2.750309 sec, iter/sec: 363595473.689393
pipe lasts: 1.836527 sec, iter/sec: 544505908.943003
sock lasts: 2.745830 sec, iter/sec: 364188561.563109
$ gcc -ggdb3 -DN=2048 -O1 bench-unixsocket-pipe.c                                                                                                                                                                   
$ taskset -c 2,3 ./a.out 1000000000 $((16*1024*1024))
pipe lasts: 0.729964 sec, iter/sec: 1369930904.096325
sock lasts: 0.728934 sec, iter/sec: 1371865572.857027
pipe lasts: 0.686415 sec, iter/sec: 1456843713.974395
sock lasts: 0.719664 sec, iter/sec: 1389537428.464841
$ gcc -ggdb3 -DN=20480 -O1 bench-unixsocket-pipe.c
$ taskset -c 2,3 ./a.out 1000000000 $((16*1024*1024))
pipe lasts: 0.239564 sec, iter/sec: 4174254156.268338
sock lasts: 0.127470 sec, iter/sec: 7844970947.640639
pipe lasts: 0.241605 sec, iter/sec: 4138993031.587193
sock lasts: 0.128974 sec, iter/sec: 7753475456.606051
$ gcc -ggdb3 -DN=204800 -O1 bench-unixsocket-pipe.c
$ taskset -c 2,3 ./a.out 5000000000 $((16*1024*1024))
pipe lasts: 1.094997 sec, iter/sec: 4566223902.796374
sock lasts: 0.410690 sec, iter/sec: 12174630503.981833
pipe lasts: 1.093797 sec, iter/sec: 4571230275.116221
sock lasts: 0.415574 sec, iter/sec: 12031541031.321995

bench-unixsocket-pipe.c

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <inttypes.h>
#include <fcntl.h>
//#include <linux/fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>

#ifndef N
#define  N (512*4)
#endif
static char buf[N + sizeof(int)] = {};
int
fullwrite(int fd, void* buf, int sz)
{
	while (sz > 0) {
		int r = write(fd, buf, sz);
		if (r <= 0) {
			_exit(1);
		}
		buf += r;
		sz -= r;
	}
	return 1;
}

void
writer(int fd, int64_t total)
{
	int r;
	while (total > 0) {
		int rand = random() % N;
		#if 0
		fullwrite(fd, &rand, sizeof(rand));
		fullwrite(fd, buf, rand + 4);
		#else
		*(int*)buf = rand;
		fullwrite(fd, buf, rand + 4);
		#endif
		total -= rand;
	}
	close(fd);
}

int
fullread(int fd, void* buf, int sz)
{
	while (sz > 0) {
		int r = read(fd, buf, sz);
		if (r <= 0) {
			return 0;
		}
		buf += r;
		sz -= r;
	}
	return 1;
}

void
reader(int fd)
{
	int sz;
	char buf[N];
	int r;
	while (fullread(fd, &sz, sizeof(sz))) {
		if (!fullread(fd, buf, sz)) exit(1);
	}
	close(fd);
}

#define F_SETPIPE_SZ 1031
int main(int argc, char** argv)
{
	int64_t total = 1000000000;
	int pipebuf = 65*1024;
	if (argc > 1) total = atoll(argv[1]);
	if (argc > 2) pipebuf = atoi(argv[2]);
	for (int kk=2; kk; kk--) {
	int r;
	int pipefd[2];
	r = pipe(pipefd); (void)r;
	r = fcntl(pipefd[1], F_SETPIPE_SZ, pipebuf);
	if (r != 0) {
		//printf("fcntl: %d\n", r);
	}
	int sockfd[2];
	r = socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, sockfd); (void)r;

	struct timespec ts = {}, tstop;
	double d;

	clock_gettime(CLOCK_MONOTONIC, &ts);
	if (fork()) {
		close(pipefd[1]);
		reader(pipefd[0]);
	} else {
		writer(pipefd[1], total);
		_exit(0);
	}
	clock_gettime(CLOCK_MONOTONIC, &tstop);
	d = (tstop.tv_sec - ts.tv_sec) + (tstop.tv_nsec - ts.tv_nsec) * 1e-9;
	printf("pipe lasts: %f sec, iter/sec: %f\n", d, total/d);

	clock_gettime(CLOCK_MONOTONIC, &ts);
	if (fork()) {
		close(sockfd[1]);
		reader(sockfd[0]);
	} else {
		writer(sockfd[1], total);
		_exit(0);
	}
	clock_gettime(CLOCK_MONOTONIC, &tstop);
	d = (tstop.tv_sec - ts.tv_sec) + (tstop.tv_nsec - ts.tv_nsec) * 1e-9;
	printf("sock lasts: %f sec, iter/sec: %f\n", d, total/d);
	}
}