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Date: Wed, 5 Jun 2013 16:47:42 +0200
From: Luigi Rizzo <rizzo@iet.unipi.it>
To: Chao Xu <caesarxuchao@gmail.com>
Subject: Re: netmap on wireless NIC
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On Wed, Jun 05, 2013 at 09:28:00AM -0500, Chao Xu wrote:
> Thank you Adrian and Luigi. My goal is to reduce the latency, i.e. get the
> packet as soon as it arrives on the NIC, and send the packet from user
> space to NIC quickly. I think netmap will help because it skips the socket
> layer and kernel network stack.

the difference is completely negligible.
we are talking about 1us or less

cheers
luigi

> 
> On Wed, Jun 5, 2013 at 8:45 AM, Luigi Rizzo <rizzo@iet.unipi.it> wrote:
> 
> > On Tue, Jun 04, 2013 at 04:06:35PM -0500, Chao Xu wrote:
> > > Hello,
> > >
> > > Is it possible to hacking some wireless NIC driver (carl9170 for example)
> > > to enable netmap on it? I guess this is possible because wireless drivers
> > > also manage packets using ring buffers. My goal is to access the raw
> > > packets as quickly as possible, not to achieve high data rate. Is there
> > any
> > > argument against doing so? Thank you.
> >
> > as other said, there is no negative argument but it does not
> > seem worthwhile, because at least with current packet rates
> > you should be able to extract packets using pcap.
> > Unless, of course, you are running a 300Mbit/s interface
> > on a slow embedded CPU, in which case the efficiency of
> > netmap might be helpful.
> >
> > cheers
> > luigi
> >
> 
> 
> 
> -- 
> Regards,
> Chao Xu