[USRP-users] High CPU utilization (100%) when streaming two concurrent channels regardless of sample rate

Josh Blum josh at ettus.com
Mon Apr 1 13:13:42 EDT 2013


On 04/01/2013 11:45 AM, Pruitt, Paul N. wrote:
> I am using an N210 with this software configuration:
> 
>     linux; GNU C++ version 4.4.6 20120305 (Red Hat 4.4.6-4);
> Boost_104400;
> 
>     UHD_003.005.000-27-gfcfcc01f
> 
>  
> 
> When I stream data from one DDC using sc16 wire format at 1 MSPS,
> according to htop, the CPU utilization is ~1% for the conversion thread
> and nearly the same for the application thread that receives the data
> and currently does nothing with it. At 10 MSPS, the CPU utilization is
> 16% for each of these threads. Very reasonable.
> 
>  

The n>1 converter threads are actually spinning and thread yielding when
there are multiple channels per streamer. So, one of the effects is that
you would see CPU usage climb up for the core hosting that thread.

Is it a problem BTW? This could be addressed with condition variables
pretty easily.

-josh




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