Measuring Network Packet processing time

Peter Senna Tschudin peter.senna at gmail.com
Tue Apr 8 09:35:29 EDT 2014


You need to know exactly what you are doing for using rdtsc. There are
some external factors that affect the counting such as dynamic clock,
and out of order execution. I'm not sure that rdtsc registers are
synchronized on different CPUs. Some code for you to play with:
https://github.com/petersenna/rdtscbench
https://github.com/petersenna/Kernel/tree/master/stopwatch

On Mon, Apr 7, 2014 at 3:21 PM, Sunny <sundarcs at gwu.edu> wrote:
> Hi all,
>
> I'm running xen 4.2 on Linux Kernel 3.7 and I'm trying to figure out the time taken(latency) by a network packet to reach it's destination VM from the time it arrives at the NIC. What do you think is the best way to do it? I was thinking may be add rdtsc timestamp to the IP options header on arrival, and one more when it reaches to its desired VM and examine the two timestamps. I've not figured out a way to do this yet--but do you think this is a viable option or what other methods would you recommend?
>
> Thanks,
> Sunny
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-- 
Peter



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