tcpdump mailing list archives
Hardware timestamp ?
From: Pierre Karampournis <pkarampournis () gmail com>
Date: Thu, 26 Feb 2009 18:49:45 -0600
Hi,I am currently working in a university lab and I need to capture packets with a nanosecond precision timestamp using the Pcap format.
Pcap format allows nanosecond timestamping (even if it is not implemented in libpcap yet) so I tried to modify libPcap and Tcpdump to realize that. But my first naive and ugly modification was erasing the kernel timestamp (currently in microseconds) by a user timestamp (in nanosecond of course) so I loose precision trying to gain precision... Thinking about that, user timestamping is imprecise due to scheduling and other factors, but kernel timestamping, even if it is a lot better, isn't really accurate too.
So I read few things about using hardware timestamping and I wonder if something like that is being developed in libPcap or if solutions exists ?
With current networks bandwidth, why the time precision still isn't better ? Thank you, Pierre - This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe.
Current thread:
- Hardware timestamp ? Pierre Karampournis (Feb 26)
- Re: Hardware timestamp ? Guy Harris (Feb 26)
- Re: Hardware timestamp ? Guy Harris (Feb 27)
- Re: Hardware timestamp ? Pierre KARAMPOURNIS (Feb 27)
- Re: Hardware timestamp ? Guy Harris (Feb 27)
- Re: Hardware timestamp ? Pierre Karampournis (Mar 02)
- Re: Hardware timestamp ? Stephen Donnelly (Mar 02)
- Re: Hardware timestamp ? Guy Harris (Feb 27)
- Re: Hardware timestamp ? Guy Harris (Feb 26)
- Re: Hardware timestamp ? Pierre KARAMPOURNIS (Feb 27)
- Re: Hardware timestamp ? Pierre KARAMPOURNIS (Feb 27)