Loading ...
Sorry, an error occurred while loading the content.

CW Skimmer - more

Expand Messages
  • Pete Smith
    Now that I ve proved (to myself at least) that I m not completely nuts, let me prevail on your patience with a slightly more complicated question. Under normal
    Message 1 of 1 , Nov 11, 2008
      Now that I've proved (to myself at least) that I'm not completely nuts, let
      me prevail on your patience with a slightly more complicated question.

      Under normal circumstances, I understand that CW Skimmer's own CPU usage
      indicator will normally show a somewhat higher number than Task Manager's,
      because it is looking at peaks from one application while Task Manager
      looks at an average over a second of so of all the processes that are going on.

      That being said, I find that there is a pretty logical and explicable
      relationship among the Skimmer CPU number, the bandwidth set on the Radio
      tab, the number of decoders, and the number of candidate data streams (the
      last two are the "98 of 456 decoders" numbers).

      Incidentally, it's little-known, but the Sample Rate choice on the Radio
      tab *does* affect both the bandwidth covered by an SDR-IQ when used with
      Skimmer and (therefore) the CPU demand. To verify this, bring up Skimmer
      and change from 48 to 96 KHz. You'll see the CPU loading go 'way up.

      Finally, here's the question. Have you ever noticed a situation in which
      the CPU utilization of the total of the two Skimmer processes) as reported
      by Task Manager is much higher than the CPU utilization being reported by
      Skimmer? I see this all the time, but have not been able to figure out
      what causes it, or what makes it go away. All I know for sure is that
      sometimes something is happening to impose a much higher load on the CPU
      for a given number of decoders than is the case at other times. Sometimes
      I'll see this as much higher CPU utilization in 48 KHz mode than in 96 KHz
      mode. Sometimes I can cause things to revert to normal by changing Sample
      rates, stopping and restarting the waterfall, or restarting the program.

      One good question that Alex asked was whether it might be a mistake by the
      Task Manager. All I can say is that I don't think so, because there is a
      definite slowing of other programs when Task Manager says utilization is
      over 85 percent, even though Skimmer itself says it is only using 50-55
      percent. Moreover, I see the same phenomenon in Process Explorer, which is
      a completely separate program - I can't be sure that it doesn't measure CPU
      utilization the same way, of course, but it seems to be a stretch, because
      Process Explorer was not developed by Microsoft.

      Anyway that's the question - if you could, just keep your eyes peeled, or
      run some tests, whatever you have time for.

      Thanks and

      73, Pete N4ZR
      the World Contest Station Database is back...
    Your message has been successfully submitted and would be delivered to recipients shortly.