Ho ok.
On 25/11/13 21:28, Guy Harris wrote:
On Nov 25, 2013, at 11:01 AM, Eliezer Croitoru<elie...@ngtech.co.il> wrote:
>I am running Linux on couple systems: Gentoo, Ubuntu 10.04+newers, CentOS.
What kernel version?
I have one 2.6.32-X in the CentOS.
Ubuntu has 3.2+ kernels(3.2,3.4,3.7..)
Gentoo is another story but it's similar.
>On the ubuntu that I am using now:
>tcpdump version 4.4.0
>libpcap version 1.4.0
>
>On the CentOS it's the exact same version output:
If you're running on a system with a 3.2 or later kernel, then, if you use
libpcap built from the current Git trunk, it can use version 3 of the
memory-mapped capture mechanism (TPACKET_V3), which makes more efficient use of
the capture mechanism's buffers than do earlier versions of that mechanism
(TPACKET_V1 and TPACKET_V2), resulting in fewer packet drops.
I hope ubuntu have support for these but it seems like 2MB on linux can
be increased easily to more then 50MB on this machine since I do have
lots of ram free (6GB) is more then is needed for the task from my way
of thinking.
I will try to test it later.
Thanks again,
Eliezer
>So In a case there is not much ram limitation for the machine I would thing
that an option to use more ram for these buffers can be an option.
Yes - that's what the -B flag to tcpdump lets you do. (The default is 2MB on
Linux.)
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