1 files changed, 107 insertions, 0 deletions
diff --git a/bench.c b/bench.c
new file mode 100644
index 0000000..8e0f091
--- /dev/null
+++ b/bench.c
@@ -0,0 +1,107 @@
+#define _GNU_SOURCE
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+
+#define N  100000
+
+
+static void
+print_dur(struct timespec *start, struct timespec *end, int nlog, const char *sys)
+{
+	end->tv_sec -= start->tv_sec;
+	if ((end->tv_nsec -= start->tv_nsec) < 0) {
+		end->tv_sec -= 1;
+		end->tv_nsec += 1000000000L;
+	}
+	printf("%-10s 1<<%i %li.%09li\n", sys, nlog, end->tv_sec, end->tv_nsec);
+	fflush(stdout);
+}
+
+
+int
+main(void)
+{
+	char *buf = malloc(1 << 25);
+	int i, nlog;
+	int rw[2];
+	size_t n, p;
+	ssize_t r;
+	struct timespec start, end;
+	struct iovec iov;
+
+	memset(buf, 0, 1 << 25);
+
+	for (nlog = 0; nlog <= 25; nlog++) {
+		n = 1 << nlog;
+
+		socketpair(PF_UNIX, SOCK_STREAM, 0, rw);
+		if (!fork()) {
+			close(rw[1]);
+			while (read(rw[0], buf, n) > 0);
+			exit(0);
+		} else {
+			close(rw[0]);
+			clock_gettime(CLOCK_MONOTONIC, &start);
+			for (i = 0; i < N; i++)
+				for (p = 0; p < n; p += (size_t)r)
+					if ((r = write(rw[1], buf + p, n - p)) < 0)
+						return perror("write <socket>"), 1;
+			close(rw[1]);
+			wait(NULL);
+			clock_gettime(CLOCK_MONOTONIC, &end);
+			print_dur(&start, &end, nlog, "socketpair");
+		}
+
+		pipe(rw);
+		if (!fork()) {
+			close(rw[1]);
+			while (read(rw[0], buf, n) > 0);
+			exit(0);
+		} else {
+			close(rw[0]);
+			clock_gettime(CLOCK_MONOTONIC, &start);
+			for (i = 0; i < N; i++)
+				for (p = 0; p < n; p += (size_t)r)
+					if ((r = write(rw[1], buf + p, n - p)) < 0)
+						return perror("write <pipe>"), 1;
+			close(rw[1]);
+			wait(NULL);
+			clock_gettime(CLOCK_MONOTONIC, &end);
+			print_dur(&start, &end, nlog, "pipe");
+		}
+
+		pipe(rw);
+		if (!fork()) {
+			close(rw[1]);
+			while (read(rw[0], buf, n) > 0);
+			exit(0);
+		} else {
+			close(rw[0]);
+			clock_gettime(CLOCK_MONOTONIC, &start);
+			for (i = 0; i < N; i++) {
+				iov.iov_base = buf;
+				iov.iov_len = n;
+				for (p = 0; p < n; p += (size_t)r) {
+					r = vmsplice(rw[1], &iov, 1, 0);
+					if (r < 0)
+						return perror("vmsplice <pipe>"), 1;
+					iov.iov_base += r;
+					iov.iov_len -= (size_t)r;
+				}
+			}
+			close(rw[1]);
+			wait(NULL);
+			clock_gettime(CLOCK_MONOTONIC, &end);
+			print_dur(&start, &end, nlog, "vmsplice");
+		}
+	}
+	return 0;
+}