[Winpcap-users] Timing problems

[Gianluca Varenni]

----- Original Message ----- 
From: "Cyril Dupuit" <cyrildupuit at hotmail.com>
To: <winpcap-users at winpcap.org>
Sent: Wednesday, February 06, 2008 12:05 PM
Subject: [Winpcap-users] Timing problems


> Hello,
> I am developping an application under XP using winpcap to measure time 
> stamping between packets.
> It works fine but it is not very precise.
> The cpu load modify the real packet timings.
> There is a way to have a better timing efficiency with an option of 
> winpcap or it is impossible ?

It depends on how precise you want your timestamps. Please remember that 
packets are timestamped when they reach the winpcap protocol driver, so 
after the network card has notified the OS about them, and after the network 
card driver has notified the upper layers (among which winpcap).
WinPcap does its best to timestamp packets as soon as possible, what happens 
during high cpu load is that probably the network card (among other things) 
batches the delivery of packets to the OS, thus introducing a jitter in the 
timestamping.

Hope it helps
GV


>
> Thank you in advance,
> Cyril
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