I have also now observed that adding a global reverb instrument (stereo 
reverbsc) to my test .csd (8 instruments) causes overall CPU usage to 
skyrocket from 5-6% to 80%. So, no optional reverb/depth for the OLPC.

To summarize what I've found it necessary to do to port my .csd's to OLPC 
(i.e., keep to reasonable, glitch-free CPU usage):

Reduce the 16 voices to 8
Reduce the SR from 44100 to 36000
Increase ksmps from 10 to 100
Eliminate optional reverb/depth processing

I can live with this, so far at least. (Sounds a bit like our current 
economic situation, doesn't it?)

Art Hunkins

----- Original Message ----- 
From: "Victor Lazzarini" 
To: 
Sent: Tuesday, January 13, 2009 1:07 PM
Subject: [Csnd] Re: Re: Re: SR and CPU Usage on the OLPC?


>I suppose you are doing many more calculations at kr, so this
> is what is making it heavy. ksmps=100 is I think very acceptable.
>
> Regards
>
> Victor
> At 17:51 13/01/2009, you wrote:
>>Victor,
>>
>>Thanks for this very helpful observation. It led to the solution to my 
>>problem. It indeed turns out that the control rate is considerably more 
>>important than SR in regard to CPU usage.
>>
>>Data:
>>SR=44100, ksmps=10: csound CPU usage=98, overall CPU usage=95
>>SR=36000, ksmps=10: csound CPU=61, overall CPU=71
>>SR=36000, ksmps=100: csound CPU=4, overall CPU=5
>>
>>The latter is a *dramatic* difference - one I can live with. Finally, 
>>"sensekey tamed."
>>
>>(Any explanations greatly appreciated.)
>>
>>Thanks again, Victor.
>>
>>Art Hunkins
>>
>>----- Original Message ----- From: "victor" 
>>To: 
>>Sent: Tuesday, January 13, 2009 3:57 AM
>>Subject: [Csnd] Re: SR and CPU Usage on the OLPC?
>>
>>
>>>I also noticed that changing the control rate also makes
>>>a great deal of difference.
>>>
>>>Victor
>>>----- Original Message ----- From: "Art Hunkins" 
>>>To: 
>>>Sent: Tuesday, January 13, 2009 3:40 AM
>>>Subject: [Csnd] SR and CPU Usage on the OLPC?
>>>
>>>
>>>>Does anyone have an explanation for the following bizarre (but verified) 
>>>>data regarding SR's and CPU usage on the OLPC? My test .csd is with 
>>>>ksmps=10, realtime, with MIDI input.
>>>>
>>>>SR=44100: Csound CPU usage = 26%, total CPU usage = 54%
>>>>(SR=48000: 32% and 52%)
>>>>SR=36000: 4% and 6%
>>>>SR=32000: 3% and 5%
>>>>SR=22050: <3% and 4%
>>>>
>>>>All conditions, to my knowledge, except for SR, were identical.
>>>>
>>>>It makes no sense to me, but the difference is real. I'll be using 
>>>>SR=32000 or 36000 instead of 44100.
>>>>
>>>>Whatever the reason, I'll now be able to port *some* of what I'd hoped 
>>>>to the OLPC.
>>>>
>>>>Art Hunkins
>>>>
>>>>
>>>>Send bugs reports to this list.
>>>>To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe 
>>>>csound"
>>>
>>>
>>>
>>>Send bugs reports to this list.
>>>To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe 
>>>csound"
>>
>>
>>
>>Send bugs reports to this list.
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>>csound"
>
> Victor Lazzarini
> Music Technology Laboratory
> Music Department
> National University of Ireland, Maynooth
>
>
> Send bugs reports to this list.
> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe 
> csound"