Date: Sun, 31 Oct 2004 01:47:51 -0800 From: Sean Chittenden <sean@chittenden.org> To: freebsd-net@freebsd.org Subject: Irritation regarding precision of ping(8)... Message-ID: <EE1B194A-2B21-11D9-8420-000A95C705DC@chittenden.org>
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This has long bugged me and tonight I finally snapped and had to do
something about it. Example output:
64 bytes from a.b.c.d: icmp_seq=935 ttl=126 time=33.824 ms
64 bytes from a.b.c.d: icmp_seq=936 ttl=126 time=29.138 ms
64 bytes from a.b.c.d: icmp_seq=937 ttl=126 time=28.262 ms
64 bytes from a.b.c.d: icmp_seq=938 ttl=126 time=29.67 ms
64 bytes from a.b.c.d: icmp_seq=939 ttl=126 time=30.963 ms
64 bytes from a.b.c.d: icmp_seq=940 ttl=126 time=30.283 ms
64 bytes from a.b.c.d: icmp_seq=941 ttl=126 time=29.455 ms
The source of irritation being line seq 930. The time should be 29.670
since we are accurately measuring the precision to the thousands place.
On a less scientific basis (and the actual reason this bothered me),
not having the trailing zero disrupts the continuity of a stream of
ping times. The attached patch simply fixes the various formatting
statements introduced in version 1.2(!!!!) to use %.30f instead of
%.3f. It's now possible to see '28.200' ms ping times instead of just
'28.2 ms'.
Anyone mind if I commit the attached patch? I'm sure I'm not the only
one who's wanted to commit the following. -sc
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Index: ping.c
===================================================================
RCS file: /home/ncvs/src/sbin/ping/ping.c,v
retrieving revision 1.106
diff -u -r1.106 ping.c
--- ping.c 30 Sep 2004 07:35:56 -0000 1.106
+++ ping.c 31 Oct 2004 09:40:35 -0000
@@ -998,7 +998,7 @@
seq);
(void)printf(" ttl=%d", ip->ip_ttl);
if (timing)
- (void)printf(" time=%.3f ms", triptime);
+ (void)printf(" time=%.30f ms", triptime);
if (dupflag)
(void)printf(" (DUP!)");
if (options & F_AUDIBLE)
@@ -1293,7 +1293,7 @@
double avg = tsum / n;
double vari = tsumsq / n - avg * avg;
(void)printf(
- "round-trip min/avg/max/stddev = %.3f/%.3f/%.3f/%.3f ms\n",
+ "round-trip min/avg/max/stddev = %.30f/%.30f/%.30f/%.30f ms\n",
tmin, avg, tmax, sqrt(vari));
}
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Sean Chittenden
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