Re: [Discuss-gnuradio] More on latency

[Eric Blossom]

On Thu, Oct 21, 2010 at 12:41:16AM -0400, Marcus D. Leech wrote:
> I had a flow-graph that earlier today had a latency of roughly 1 second
> or so.
> 
> When I tested it this evening, after it had been running for several
> hours, the latency was
>   back up to *several tens of seconds*!!!.  Which means that external
> events at the source take
>   several tens of seconds to show up at the sinks -- two graphical, and
> one filesink.  WTF? !!
> 
> The CPU load at the time was modest -- about 38%

38% of what?  How many cores?  What kind of machine?

It's possible that there's a computation in a single block that
requires > 1 core to compute in realtime.

Have you tried oprofile to see where the graph is spending its time?
Are you i/o bound?  What's the rate that you're writing to the file sink?

I believe htop will show you all the threads of the process.  Are any
of them consuming on the order of 100% of a single core?

Eric