Re: libpcap capture performance drop

[Miroslav Lichvar <mlichvar () redhat com>]

On Fri, Aug 13, 2010 at 02:00:22PM -0700, Guy Harris wrote:
> No.  I forgot that the availability of the memory-mapped pcap
> mechanism isn't determined by the configure script, it's determined
> by what the system includes offer.
>
> Instead, in pcap-linux.c, just #if 0 out the
>
>  /* check for memory mapped access avaibility. We assume every needed
>   * struct is defined if the macro TPACKET_HDRLEN is defined, because it
>   * uses many ring related structs and macros */

Would it be possible to support disabling mmaped access in runtime
with an environment variable?

I had one user complaining about slow startup of tcpdump -s 0 and it
seems that there is not much we can do about it as kernel has to
allocated large blocks of continuous memory.

-- 
Miroslav Lichvar
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