[Skimmertalk] CW Skimmer - more

[W7TMT]

Pete, Dave et al,

Yesterday I moved Skimmer and my SDR-IQ software to a laptop. The desktop I
was running on had dual processors and a ton of memory and never breaks into
a sweat so I thought perhaps moving it to a less powerful platform might be
more realistic. It is currently running on an HP laptop with 1.7 GHz single
core processor and 1 GB of memory.

After having monitored it for a few days on the desktop I was rather
surprised at how hard it makes the laptop work. (Although Skimmer is not
nearly as demanding as the SpectraVue application.) I can easily get CPU
usage up in the 50-70% zone whenever the band opens a bit and the numbers of
decoders go up. Opening a couple of other non-related applications I can
take it up into the 90% utilization range pretty easily and get the machine
to start swapping memory to the hard disk. 

This morning while running it on 40M around our sunrise I saw more than 150
decoders running pretty steadily for about an hour. CPU usage was up in the
75-85% zone for most of that time. I tried a number of things - I  started
by opening additional apps so I could force Page File usage and monitor it
with Process Explorer. I then stopped and started the waterfall, changed the
Sampling Rate between 48 and 96 kHz and even once moved it up to 192 kHz. I
tweaked all the applicable Skimmer settings and could not reproduce the high
usage symptom Pete is reporting. I tried running the Skimmer window nearly
full screen and reducing it to an inch square etc. (Amazing how much that
affects the utilization.) Every change resulted in levels that seemed to
reflect the averages I was seeing last night when I first set it up on this
machine and ran it relatively "stress free" to get some base line  numbers.
At times I had the machine loaded to the point that the audio from  Skimmer
was unusable but I never saw any spikes in CPU utilization that seemed out
of line. I've got it running now on 20M with a couple of apps plus Process
Explorer open and have overall CPU usage in the low 70's. I'll monitor it
further but so far I can't reproduce the problem here. Perhaps it's a memory
leak issue and only manifests itself after some period of time. I made some
notes and will watch for that. Pete if you have something specific you want
me to try let me know.

73/Patrick
W7TMT
 
 

> -----Original Message-----
> From: skimmertalk-bounces at contesting.com 
> [mailto:skimmertalk-bounces at contesting.com] On Behalf Of Pete Smith
> Sent: Wednesday, November 12, 2008 3:08 AM
> To: k1ttt at arrl.net; skimmertalk at contesting.com
> Subject: Re: [Skimmertalk] CW Skimmer - more
> 
> I really don't think so, Dave.  Nothing else changes, and it 
> does not appear that this issue is triggered by external 
> events.  Instead, it is as if Skimmer itself has 2 different 
> states - one in which it uses much more CPU than the other.  
> It toggles into the "gluttonous" state. usually at startup or 
> when you stop and restart the waterfall or change the Sample 
> Rate.  It will go from a lower CPU utilization to one that is 
> much higher, while nothing else changes, either on the band 
> being monitored or in any of the other programs.  Once it has 
> switched, it stays high until some right combination of 
> events causes it to toggle back into the normal CPU utilization.
> 
> 73, Pete
> 
> K1TTT wrote:
> >If what I suspect is right then it would only happen when 
> windows needs 
> >extra overhead time to swap processes.  Watch some of the 
> other columns 
> >when that happens, see if the pagefault or working set 
> deltas are high 
> >when that happens.  Those are signs that windows is having 
> to do extra 
> >work to manage memory, especially pagefaults.
> >
> >
> >David Robbins K1TTT
> >e-mail: mailto:k1ttt at arrl.net
> >web: http://www.k1ttt.net
> >AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
> >
> >
> > > -----Original Message-----
> > > From: skimmertalk-bounces at contesting.com [mailto:skimmertalk- 
> > > bounces at contesting.com] On Behalf Of Pete Smith
> > > Sent: Tuesday, November 11, 2008 23:04
> > > To: skimmertalk at contesting.com
> > > Subject: Re: [Skimmertalk] CW Skimmer - more
> > >
> > > I don't have any trouble with the Task Manager number 
> being larger, 
> > > but why only some of the time?  Something makes the relationship 
> > > between the two numbers flip unexpectedly, and when it does, my 
> > > other programs slow down.
> > >
> > > 73, Pete
> > >