Josh,
Thank you so much for the suggestion. I will try this. I have 4GB of ram and a
4GB swapfile size. Do you recommend any particular setting for
set_max_output_buffer(long max_output_buffer)?
Should I leave tb.run() as is, or modify the number of n_output_items in
conjunction with the
void set_max_output_buffer(long max_output_buffer)?
Also, do you recommend any particular settings using uhd_usrp_probe
--args="serial=123456, recv_frame_size=XXXX,num_recv_frames=XXXX",
send_frame_size=XXXX,send_recv_frames=XXX"
or should I leave it default? The custom 4 channel usrp block in the older
gnuradio version had the fusb_block and fusb_nblocks both set to 512*32
Thanks, -Tom
________________________________
From: Josh Blum <j...@ettus.com>
To: discuss-gnuradio@gnu.org
Sent: Friday, March 1, 2013 2:55 PM
Subject: Re: [Discuss-gnuradio] LibUSRP vs LibUHD Performance on older machines
On 03/01/2013 04:51 PM, Tom Hendrick wrote:
> Hello all,
>
> I've had trouble making a 4 channel USRP samples at 1Ms/s write to file at
> 500 kS/s with ubuntu 12.04 and libuhd. I am getting several overruns and I
> had tried adjusting some of the parameters using usrd_probe_devices but with
> no success. I have a laptop with a duo core centrino processor which should
> be enough.
>
> I've made this 4 channel work successfully with the same exact laptop and
> with ubuntu 10.04 and the older version of gnuradio that uses libusrp. I get
> no underruns at all even for an entire hour of writing to file.
>
>
> Has anyone else experienced performance differences between libusrp and
> libuhd? I just want to make sure it isn't a configuration problem or
> something I'm doing wrong causing the overruns. If its likely an issue with
> libuhd, I guess I will just keep a backup of ubuntu 10.04 and gnuradio
> libusrp version installation files and leave my dual boot setup intact.
>
> Thank you very much, - Tom
>
>
You might try setting a very large output buffer on the usrp source
block. I heard this helps (you should be able to call this in python
after the block constructs):
/*!
* \brief Sets max buffer size on all output ports.
*/
void set_max_output_buffer(long max_output_buffer)
-josh
>
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