[Xen-users] Ping RTT is rounded on domu

[Ian Baber <ian@xxxxxxxxxxx>]

I'm setting up a network monitoring program on a domu.  domu and dom0 
are running the debian 2.6.26-2-xen-686 kernel.  All ping round trip 
times are an even integer number of milliseconds.  I've seen other posts 
on the list about strange RTT times, but they seem to deal with large 
changes caused by domu/dom0 clock synchronization.  I am already using 
the extra="clocksource=jiffies" option as described on the debian wiki 
(http://wiki.debian.org/Xen). 

This causes all systems on my lan to report a 0.00ms ping time. The 
rounding only occurs on the domu system, the dom0 can accurately measure 
ping rtt <1ms.  I'm trying to use this system to diagnose intermittent 
VoIP problems I've had on our network, and accurate ping times on the 
lan as well as to our VoIP providers would be nice. 

At this point, I'm not even sure what to google next.  If anyone has a 
fix or can at least point me in the right direction I'd be grateful.
Output from ping:


PING [host] (x.x.x.x) 56(84) bytes of data.
64 bytes from [host] (x.x.x.x): icmp_seq=1 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=2 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=3 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=4 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=5 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=6 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=7 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=8 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=9 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=10 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=11 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=12 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=13 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=14 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=15 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=16 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=17 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=18 ttl=48 time=48.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=19 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=20 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=21 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=22 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=23 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=24 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=25 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=26 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=27 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=28 ttl=48 time=72.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=29 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=30 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=31 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=32 ttl=48 time=60.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=33 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=34 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=35 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=36 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=37 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=38 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=39 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=40 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=41 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=42 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=43 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=44 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=45 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=46 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=47 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=48 ttl=48 time=60.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=49 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=50 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=51 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=52 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=53 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=54 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=55 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=56 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=57 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=58 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=59 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=60 ttl=48 time=56.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=61 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=62 ttl=48 time=52.0 ms
64 bytes from [host] (x.x.x.x): icmp_seq=63 ttl=48 time=52.0 ms
^C
--- [host] ping statistics ---
63 packets transmitted, 63 received, 0% packet loss, time 62248ms
rtt min/avg/max/mdev = 48.000/54.095/72.000/3.258 ms


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