[RTTY] RTTY Skimmer Server computer hardware needed to handle WPX without throttling

[Jeff AC0C]

Pete, thanks for the comments.

On my AMD 945 (3750 passmark), I could see about 350 decoders max.

On two bands at 96 Khz, there were around 600 signals.  If that's 
representative, it's fair to assume that the max load is during the 
daytime - with 3 active bands (10/15/20).  Assuming 300 signals per band, 
and adding a bit of pad, to call it 1K signals total.

Assuming that passmark score/decoder was predictive in my case, I 
extrapolated that it would take about something with about 11K passmark to 
keep up (for the most part) skimming 5 bands @ 96 Khz on a busy RTTY 
contest.

It's interesting that your much more capable rig (2-3x higher passmark 
score) was running only 25% higher decoder count.  I've seen data that the 
AMD cpu do not provide as good of a performance as the intel for unknown 
reasons with this application (I assume it's due to some CPU or code 
optimization specific to the compiler or libraries).  However, as a separate 
data point, Wes told me his current setup (i7 hasselwel category CPU) was 
almost able to keep up in a 5x96 configuration.

Lot of assumptions and variables - so I don't have a lot of confidence in my 
conclusions.

But I do think this means the best of the current generation would be up to 
the task.  But only just so...

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message----- 
From: Pete Smith N4ZR
Sent: Wednesday, February 18, 2015 5:44 AM
To: Jeff AC0C
Cc: rbn-ops at yahoogroups.com ; RTTY Contesting ; skimmer at dxwatch.com
Subject: Re: [RTTY] RTTY Skimmer Server computer hardware needed to handle 
WPX without throttling

Hi Jeff.  For whatever it is worth, here's what I did this weekend.  I'm
running an AMD FX8350 (passmark 9000+) with 8 GB of RAM.

1.  turned off CW skimming for the weekend.
2.  Set up low band and high band rotation at sunrise and sunset,
running 4 bands at a time
3.  Limited coverage to 96 KHz
4.  Tailored my RTTY segments, starting with the "Contest" default
setting, to make sure I wasn't listening where the RTTY wasn't. The most
important change was to define two RTTY segments for 40M, 7040-7050 and
7080-7120.  I think I probably missed some Region 2 and 3 activity in
the gap, but also got rid of a lot of that pesky CW stuff.

The best I was able to get was 440 decoders. All 8 cores were engaged at
the same levels.  Whenever the CPU usage would spike over 70 percent,
throttling would occur.  The number of decoders would drop fairly
sharply (down to 350 or so), then rebound to at or near the critical level.

A preliminary look at the RBN traffic for the weekend suggests about a
quarter of the CQWWCW daily totals(all modes).  I made about 29,000
spots per day, and I don't hear very well - certainly as compared to WZ7I.

73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

On 2/17/2015 6:50 PM, Jeff AC0C wrote:
> I ran Alex’s RTTY Skimmer Server over the WPX contest weekend and had a 
> tough time decoding multiple bands without throttling, even though the PC 
> it was running on is pretty stout.
>
> If you ran RTTY Skimmer Server over WPX and managed to do so on multiple 
> bands without throttling, I would be very interested to know what your 
> computer configuration was.  I need to put together a new box for this 
> task and have no idea how to size the hardware.
>
> 73/jeff/ac0c
> www.ac0c.com
> alpha-charlie-zero-charlie
>
> _______________________________________________
> RTTY mailing list
> RTTY at contesting.com
> http://lists.contesting.com/mailman/listinfo/rtty
>

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