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Re: [fluid-dev] ALSA driver consuming too much CPU
From: |
Paul Millar |
Subject: |
Re: [fluid-dev] ALSA driver consuming too much CPU |
Date: |
Tue, 21 Nov 2006 16:40:26 +0000 |
User-agent: |
KMail/1.9.5 |
Hi Josh,
On Sunday 19 November 2006 18:06, Josh Green wrote:
> Hallo Paul,
>
> On Thu, 2006-11-16 at 22:02 +0000, Paul Millar wrote:
> > So, in terms of documentation, would you say this is more of a problem
> > with alsa than fluidsynth? If so, do you know if it's fixed with a
> > particular release of asla/libasound?
>
> I think its likely a problem with the ALSA driver code in FluidSynth,
OK, I'll put this down as a bug either in fluidsynth's ALSA code, or ALSA
itself. I guess its still under investigation.
> > Finally, are there options that further reduce CPU usage, perhaps at the
> > cost of loosing some sound fidelity?
>
> There are a few parameters you could play with to try and get less CPU
> consumption. If you just wish to limit the maximum CPU consumption, the
> best option right now is setting the synth.polyphony settings value to a
> max number of voices.
OK, I've add this as an option. Although (for me) it didn't seem to work:
fluidsynth> unable to set maxnotes (synth.polyphony) = 16
I've tried with maxnotes set to 32 and 64. The docs say values from 16--4096
are valid, but none seemed to work.
> The other option is to play with the interpolation algorithm selection.
I've added this: "linear" is pretty bad and "none" is just awful (both as
expected).
What was strange though was they didn't seem to be contributing greatly to the
load. Just roughly eye-balling a CPU usage graph suggests that changing the
interpolation doesn't affect things much.
I guess I'd have to do profiling to find out where the CPU is being used ...
something I'll put off for a rainy day.
> If for some reason you can do without reverb and/or chorus you could
> disable them (synth.reverb.active and synth.chorus.active).
I've add these, too: there might be people out there who can live
without 'em.
> You could try messing with the FluidSynth sample rate
> (synth.sample-rate), but I think that really depends on if your sound
> card can support the rate you chooose, or you'll just end up with it
> having to be converted by ALSA anyways (conversion won't be done if hw:0
> is being used, it will just fail).
OK, I should probably leave the sample rate alone. There's currently an
option for changing this, but I'll document it without suggesting people
fiddle.
> Hope that gives you a better idea of what to play with.
Definitely!
Thanks,
Paul.
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- [fluid-dev] ALSA driver consuming too much CPU, Paul Millar, 2006/11/16
- Re: [fluid-dev] ALSA driver consuming too much CPU, Garett Shulman, 2006/11/16
- Re: [fluid-dev] ALSA driver consuming too much CPU, Josh Green, 2006/11/16
- Re: [fluid-dev] ALSA driver consuming too much CPU, Paul Millar, 2006/11/16
- Re: [fluid-dev] ALSA driver consuming too much CPU, Mihail Zenkov, 2006/11/18
- Message not available
- Re: [fluid-dev] ALSA driver consuming too much CPU, Mihail Zenkov, 2006/11/21
- Re: [fluid-dev] ALSA driver consuming too much CPU, Paul Millar, 2006/11/21
- Re: [fluid-dev] ALSA driver consuming too much CPU, Mihail Zenkov, 2006/11/21
- Re: [fluid-dev] ALSA driver consuming too much CPU, Josh Green, 2006/11/19
- Re: [fluid-dev] ALSA driver consuming too much CPU,
Paul Millar <=
- Re: [fluid-dev] ALSA driver consuming too much CPU, Josh Green, 2006/11/21