eloop-bench: fix reading the last write

The last write was never read from the pipe in the run, so many
runs filled the kernel buffer causing an error which was not seen
because the pipe was blocking.

Set the pipes to non blocking and improve the exit conditions,
also ensuring the bench returns any error back.
While here add more timings and run critera.

Thanks to Christos Zoulas for helping.

1 files changed, 51 insertions, 33 deletions

diff --git a/tests/eloop-bench/eloop-bench.c b/tests/eloop-bench/eloop-bench.c
index e7fd5a73..813fedf1 100644
--- a/tests/eloop-bench/eloop-bench.c
+++ b/tests/eloop-bench/eloop-bench.c
@@ -26,7 +26,9 @@
  */
 
 #include <sys/resource.h>
+
 #include <err.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
@@ -59,38 +61,37 @@ static void
 read_cb(void *arg)
 {
 	struct pipe *p = arg;
-	unsigned char c;
-	ssize_t l;
+	unsigned char buf[1];
 
-	l = read(p->fd[0], &c, sizeof(c));
-	if (l == -1)
+	if (read(p->fd[0], buf, 1) != 1) {
+		warn("%s: read", __func__);
 		bad++;
-	else
-		good += (size_t)l;
-	if (writes) {
-		p = (struct pipe *)arg;
-		l = write(p->fd[1], "e", 1);
-		if (l != 1)
+	} else
+		good++;
+
+	if (writes != 0) {
+		writes--;
+		if (write(p->fd[1], "e", 1) != 1) {
+			warn("%s: write", __func__);
 			bad++;
-		else {
-			writes -= (size_t)l;
-			fired += (size_t)l;
-		}
+		} else
+			fired++;
 	}
 
-	if (writes == 0) {
-		if (good == fired)
-			eloop_exit(e, EXIT_SUCCESS);
+	if (writes == 0 && fired == good) {
+		//printf("fired %zu, good %zu, bad %zu\n", fired, good, bad);
+		eloop_exit(e, good == fired && bad == 0 ?
+		    EXIT_SUCCESS : EXIT_FAILURE);
 	}
 }
 
-static struct timespec *
-runone(void)
+static int
+runone(struct timespec *t)
 {
 	size_t i;
 	struct pipe *p;
-	static struct timespec _ts;
 	struct timespec ts, te;
+	int result;
 
 	writes = nwrites;
 	fired = good = 0;
@@ -98,28 +99,27 @@ runone(void)
 	for (i = 0, p = pipes; i < nactive; i++, p++) {
 		if (write(p->fd[1], "e", 1) != 1)
 			err(EXIT_FAILURE, "send");
+		writes--;
+		fired++;
 	}
 
 	if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1)
 		err(EXIT_FAILURE, "clock_gettime");
-	(void) eloop_start(e, NULL);
+	result = eloop_start(e, NULL);
 	if (clock_gettime(CLOCK_MONOTONIC, &te) == -1)
 		err(EXIT_FAILURE, "clock_gettime");
 
-	timespecsub(&te, &ts, &_ts);
-	return &_ts;
+	timespecsub(&te, &ts, t);
+	return result;
 }
 
 int
 main(int argc, char **argv)
 {
-	int c;
+	int c, result, exit_code;
 	size_t i, nruns = 25;
 	struct pipe *p;
-	struct timespec *ts;
-
-	if ((e = eloop_new()) == NULL)
-		err(EXIT_FAILURE, "eloop_init");
+	struct timespec ts, te, t;
 
 	while ((c = getopt(argc, argv, "a:n:r:w:")) != -1) {
 		switch (c) {
@@ -140,6 +140,12 @@ main(int argc, char **argv)
 		}
 	}
 
+	if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1)
+		err(EXIT_FAILURE, "clock_gettime");
+
+	if ((e = eloop_new()) == NULL)
+		err(EXIT_FAILURE, "eloop_init");
+
 	if (nactive > npipes)
 		nactive = npipes;
 
@@ -148,19 +154,31 @@ main(int argc, char **argv)
 		err(EXIT_FAILURE, "malloc");
 
 	for (i = 0, p = pipes; i < npipes; i++, p++) {
-		if (pipe(p->fd) == -1)
+		if (pipe2(p->fd, O_CLOEXEC | O_NONBLOCK) == -1)
 			err(EXIT_FAILURE, "pipe");
 		if (eloop_event_add(e, p->fd[0], read_cb, p) == -1)
 			err(EXIT_FAILURE, "eloop_event_add");
 	}
 
+	printf("active = %zu, pipes = %zu, runs = %zu, writes = %zu\n",
+	    nactive, npipes, nruns, nwrites);
+
+	exit_code = EXIT_SUCCESS;
 	for (i = 0; i < nruns; i++) {
-		if ((ts = runone()) == NULL)
-			err(EXIT_FAILURE, "runone");
-		printf("%lld.%.9ld\n", (long long)ts->tv_sec, ts->tv_nsec);
+		result = runone(&t);
+		if (result != EXIT_SUCCESS)
+			exit_code = result;
+		printf("run %zu took %lld.%.9ld seconds, result %d\n",
+		    i + 1, (long long)t.tv_sec, t.tv_nsec, result);
 	}
 
 	eloop_free(e);
 	free(pipes);
-	exit(0);
+
+	if (clock_gettime(CLOCK_MONOTONIC, &te) == -1)
+		err(EXIT_FAILURE, "clock_gettime");
+	timespecsub(&te, &ts, &t);
+	printf("total %lld.%.9ld seconds, result %d\n",
+	    (long long)t.tv_sec, t.tv_nsec, exit_code);
+	exit(exit_code);
 }