From: Michal Sojka <sojkam1@fel.cvut.cz>
Date: Mon, 6 Jan 2014 12:39:13 +0000 (+0100)
Subject: Finish recvmmsg() benchmark
X-Git-Tag: fix-allnoconfig~114
X-Git-Url: http://rtime.felk.cvut.cz/gitweb/can-benchmark.git/commitdiff_plain/c8ace325585de747206daed3291c0b6bb790a81b

Finish recvmmsg() benchmark
---

diff --git a/recvmmsg/bench.sh b/recvmmsg/bench.sh
new file mode 100755
index 0000000..d2c4742
--- /dev/null
+++ b/recvmmsg/bench.sh
@@ -0,0 +1,9 @@
+#!/bin/sh
+
+for i in $(octave -q --eval "disp(round(logspace(log10(10), log10(50000), 1000))')"); do
+#    for j in $(seq 10); do
+	tr=$(../_compiled/bin/can_recvmmsg -c $i -r)
+	tm=$(../_compiled/bin/can_recvmmsg -c $i -m)
+	echo $i $tr $tm
+#    done
+done
diff --git a/recvmmsg/can_recvmmsg.c b/recvmmsg/can_recvmmsg.c
index 9dc57e0..4041f62 100644
--- a/recvmmsg/can_recvmmsg.c
+++ b/recvmmsg/can_recvmmsg.c
@@ -17,21 +17,54 @@
 
 #define CHECK(cmd) do { if ((cmd) == -1) { perror(#cmd); exit(1); } } while (0)
 
+char *dev = "vcan0";
 int count = 10000;
+enum { READ, RECVMMSG } recv_method = READ;
 
-int main(int argc, char *argv[])
+/* Subtract the `struct timespec' values X and Y,
+   storing the result in RESULT (result = x - y).
+   Return 1 if the difference is negative, otherwise 0.  */
+
+int
+timespec_subtract (struct timespec *result,
+		   struct timespec *x,
+		   struct timespec *y)
+{
+	/* Perform the carry for the later subtraction by updating Y. */
+	if (x->tv_nsec < y->tv_nsec) {
+		int num_sec = (y->tv_nsec - x->tv_nsec) / 1000000000 + 1;
+		y->tv_nsec -= 1000000000 * num_sec;
+		y->tv_sec += num_sec;
+	}
+	if (x->tv_nsec - y->tv_nsec > 1000000000) {
+		int num_sec = (x->tv_nsec - y->tv_nsec) / 1000000000;
+		y->tv_nsec += 1000000000 * num_sec;
+		y->tv_sec -= num_sec;
+	}
+
+	/* Compute the time remaining to wait.
+	   `tv_nsec' is certainly positive. */
+	result->tv_sec = x->tv_sec - y->tv_sec;
+	result->tv_nsec = x->tv_nsec - y->tv_nsec;
+
+	/* Return 1 if result is negative. */
+	return x->tv_sec < y->tv_sec;
+}
+
+
+void benchmark()
 {
 	int ss, sr;
 	struct sockaddr_can addr;
 	struct ifreq ifr;
 	struct can_frame cf;
 	int ret, i;
-	struct timespec t1, t2;
+	struct timespec t, t1, t2;
 
 	ss = socket(PF_CAN, SOCK_RAW, CAN_RAW);
 	sr = socket(PF_CAN, SOCK_RAW, CAN_RAW);
 
-	strcpy(ifr.ifr_name, "vcan0" );
+	strcpy(ifr.ifr_name, dev);
 	ioctl(ss, SIOCGIFINDEX, &ifr);
 
 	addr.can_family = AF_CAN;
@@ -55,40 +88,79 @@ int main(int argc, char *argv[])
 		}
 	}
 
-#if 0
-	fprintf(stderr, "Receiving %d frames with read()\n", count);
-	for (i = 0; i < count; i++) {
-		//fprintf(stderr, "Receiving frame %d\r", i);
-		ret = read(sr, &cf, sizeof(cf));
-		if (ret != sizeof(cf)) {
-			perror("read");
-			exit(1);
+	switch (recv_method) {
+	case READ: {
+		fprintf(stderr, "Receiving %d frames with read()\n", count);
+		clock_gettime(CLOCK_MONOTONIC, &t1);
+		for (i = 0; i < count; i++) {
+			//fprintf(stderr, "Receiving frame %d\r", i);
+			ret = read(sr, &cf, sizeof(cf));
+			if (ret != sizeof(cf)) {
+				perror("read");
+				exit(1);
+			}
 		}
+		clock_gettime(CLOCK_MONOTONIC, &t2);
+		//fprintf(stderr, "\n");
+		break;
 	}
-	//fprintf(stderr, "\n");
-#endif
-
-	fprintf(stderr, "Receiving %d frames with recvmmsg()\n", count);
-	struct mmsghdr msgs[count];
-	struct iovec iovecs[count];
-	char bufs[count][sizeof(struct can_frame)];
+	case RECVMMSG: {
+		fprintf(stderr, "Receiving %d frames with recvmmsg()\n", count);
+		struct mmsghdr msgs[count];
+		struct iovec iovecs[count];
+		char bufs[count][sizeof(struct can_frame)];
+
+		memset(msgs, 0, sizeof(msgs));
+		for (i = 0; i < count; i++) {
+			iovecs[i].iov_base         = bufs[i];
+			iovecs[i].iov_len          = sizeof(struct can_frame);
+			msgs[i].msg_hdr.msg_iov    = &iovecs[i];
+			msgs[i].msg_hdr.msg_iovlen = 1;
+		}
 
-	memset(msgs, 0, sizeof(msgs));
-	for (i = 0; i < count; i++) {
-		iovecs[i].iov_base         = bufs[i];
-		iovecs[i].iov_len          = sizeof(struct can_frame);
-		msgs[i].msg_hdr.msg_iov    = &iovecs[i];
-		msgs[i].msg_hdr.msg_iovlen = 1;
+		clock_gettime(CLOCK_MONOTONIC, &t1);
+		ret = recvmmsg(sr, msgs, count, 0, NULL);
+		clock_gettime(CLOCK_MONOTONIC, &t2);
+		if (ret == -1) {
+			perror("recvmmsg()");
+			exit(1);
+		} else if (ret != count) {
+			fprintf(stderr, "Error: Only %d messages received\n", ret);
+			exit(1);
+		}
+		break;
+	}
 	}
+	timespec_subtract(&t, &t2, &t1);
+	printf("%d us\n", t.tv_nsec/1000);
+}
 
-	ret = recvmmsg(sr, msgs, count, 0, NULL);
-	if (ret == -1) {
-		perror("recvmmsg()");
-		exit(1);
-	} else if (ret != count) {
-		fprintf(stderr, "Error: Only %d messages received\n", ret);
-		exit(1);
+int main(int argc, char *argv[])
+{
+	int opt;
+
+	while ((opt = getopt(argc, argv, "c:mr")) != -1) {
+		switch (opt) {
+		case 'c':
+			count = atoi(optarg);
+			break;
+		case 'm':
+			recv_method = RECVMMSG;
+			break;
+		case 'r':
+			recv_method = READ;
+			break;
+		default: /* '?' */
+			fprintf(stderr, "Usage: %s [-c <count>] [-r] [-m]  [interface]\n",
+				argv[0]);
+			exit(EXIT_FAILURE);
+		}
 	}
 
+	if (optind < argc)
+		dev = argv[optind];
+
+	benchmark();
+
 	return 0;
 }
diff --git a/recvmmsg/plot.gp b/recvmmsg/plot.gp
new file mode 100644
index 0000000..3e0f6dd
--- /dev/null
+++ b/recvmmsg/plot.gp
@@ -0,0 +1,21 @@
+set grid
+
+set xlabel "Number of messages"
+set ylabel "Time [{/Symbol m}s]"
+set key left reverse Left
+
+fit a1*x+b1 "data" using 1:2 via a1, b1
+fit a2*x+b2 "data" using 1:4 via a2, b2
+
+plot 'data' using 1:2 pt 7 ps 0.2 title 'read()', \
+     'data' using 1:4 pt 7 ps 0.2 title 'recvmmsg()', \
+     a1*x+b1 with lines lt 1 lc 1 lw 1 title "Linear fit for read()", \
+     a2*x+b2 with lines lt 1 lc 2 lw 1 title "Linear fit for recvmmsg()"
+
+# a1*x+b1 - a2*x-b2 = 0
+# (a1-a2)*x = b2-b1
+xeq = (b2-b1)/(a1-a2)
+print "ar = ", a1
+print "am = ", a2
+print "ar/am = ", a1/a2
+print "Intersection at x = ", xeq