[Discuss-gnuradio] Question about latency

[Matigakis Emmanouil]

Hello everyone,

I am trying to implement some relaying schemes in gnuradio which require fast response from
the relay. I only know how to use flow graphs at the moment so I made my code with flowgraphs and
the delay from receiving a packet until I retransmit it is about 10ms. I'm using USRP1 and the
sampling rate is 2MSPS and I use the autotransmit capability of USRP.

First of all I'm trying to understand where the delay comes from. I'm sure the delay is not due to
processing time of the packet because the processing is very simple. I don't know about latencies in
the kernel though. I read in a paper  that the time it takes for data  to go from user space to kernel
is only 200us.

Secondly I would like to know if using mblocks has any chance of reducing this delay. By the way is there
any documentation for the mblocks?

Thanks
Manolis