Re: [Discuss-gnuradio] number of blocks in a burst over USB

[Eric Blossom]

On Tue, May 29, 2007 at 10:26:41PM -0400, George Nychis wrote:
> 
> 
> Eric Blossom wrote:
> > It's not the number of blocks in a burst.  It's the number of blocks
> > that are allocated for asynchronous tranfers.
> > 
> > I suggest starting with:
> > 
> >   fusb_block_size = 4096
> >   fusb_nblocks = 16
> > 
> > Though after everything is working and realtime scheduling is
> > enabled (for the usrp mblocks), we may want to switch to
> > 
> >   fusb_block_size = 1024
> >   fusb_nblocks = 16
> > 
> 
> Okay, so the one of the reasons I moved d_urx->start() out of the 
> initialization code was
> that it's causing all of my machines to lockup within seconds.  I'm having a 
> hard time
> debugging this one as it is literally only seconds before things lock up.

What do you mean by "lock up"?
Is it burning CPU cycles?
Have you tried running it under gdb?
Don't enable real-time until you get this sorted out.

> Without starting the RX side, the code runs to completion without flinching
> (test_usrp_inband).  As soon as I start the RX side, lock up on all 3 
> machines I've tried
> this on.  Granted, they're all Gentoo x86 machines.  I've tried doubling the 
> USB block
> size, still a lock up.
> 
> Any ideas?

gdb is your friend.  First job is to figure out what the code is doing
when you say that it's hung.  I suspect some kind of logic error in
your server code, but I haven't looked at it.

Eric