>Number:         6197
>Category:       bin
>Synopsis:       add stddev to ping output
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people (Utility Bug People)
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Thu Sep 24 13:50:01 1998
>Last-Modified:
>Originator:     Daniel Hagerty
>Organization:
	MIT
>Release:        NetBSD 1.3.2
>Environment:
System: NetBSD repo-man.ai.mit.edu 1.3.2 NetBSD 1.3.2 (REPO_MAN) #45: Fri Jun 12 15:09:02 EDT 1998 hag@repo-man.ai.mit.edu:/fs/repo/hag/work/hacking/os/netbsd/src-stable/sys/arch/i386/compile/REPO_MAN i386


>Description:
	Patch to add standard deviation (easily derived from the
information already kept about the dataset) to ping's final output.
Idea from freebsd current ping.

Sample output:
----EXTERNAL-RTR-IHTFP-FDDI.MIT.EDU PING Statistics----
13 packets transmitted, 13 packets received, 0% packet loss
round-trip min/avg/max/stddev = 5.798/21.916/102.123/33.278 ms

>How-To-Repeat:
>Fix:
diff -uw ping.c.orig ping.c
--- ping.c.orig	Tue May  5 04:40:35 1998
+++ ping.c	Thu Sep 24 15:53:52 1998
@@ -78,6 +78,7 @@
 #include <limits.h>
 #include <string.h>
 #include <err.h>
+#include <math.h>
 #ifdef sgi
 #include <bstring.h>
 #include <getopt.h>
@@ -177,6 +178,7 @@
 double tmin = 999999999;
 double tmax = 0;
 double tsum = 0;			/* sum of all times */
+double tsumsq = 0;
 double maxwait = 0;
 
 #ifdef SIGINFO
@@ -833,6 +835,7 @@
 			(void) memcpy(&tv, icp->icmp_data, sizeof(tv));
 			triptime = diffsec(&last_rx, &tv);
 			tsum += triptime;
+			tsumsq += triptime * triptime;
 			if (triptime < tmin)
 				tmin = triptime;
 			if (triptime > tmax)
@@ -1089,10 +1092,14 @@
 	}
 	(void)printf("\n");
 	if (nreceived && (pingflags & F_TIMING)) {
-		(void)printf("round-trip min/avg/max = %.3f/%.3f/%.3f ms\n",
-			     tmin*1000.0,
-			     (tsum/(nreceived+nrepeats))*1000.0,
-			     tmax*1000.0);
+		double n = nreceived + nrepeats;
+		double avg = (tsum / n);
+		double variance = (tsumsq / (n - (avg * avg)));
+
+		printf("round-trip min/avg/max/stddev = "
+		       "%.3f/%.3f/%.3f/%.3f ms\n",
+			tmin * 1000.0, avg * 1000.0,
+		       tmax * 1000.0, sqrt(variance) * 1000.0);
 		if (pingflags & F_FLOOD) {
 			double r = diffsec(&last_rx, &first_rx);
 			double t = diffsec(&last_tx, &first_tx);
diff -uw Makefile.orig Makefile.c
--- Makefile.orig	Tue May  5 02:41:13 1998
+++ Makefile	Thu Sep 24 15:27:06 1998
@@ -5,5 +5,6 @@
 MAN=	ping.8
 BINOWN=	root
 BINMODE=4555
+LDADD+= -lm
 
 .include <bsd.prog.mk>
>Audit-Trail:
>Unformatted: