Hi
I recompiled 1.1.6 with polyphony set to 64. There doesn't seem to be a
command line option to reset parameters like this, but it shouldn't be
too hard to add one. Yes I know, use fluid_settings_setXXX in the code...
Anyway... no better. Still hits CPU above 99% (!) and distorts
accordingly.
(The pidstat command I used was
pidtat -C fluidsynth - u -r 5
for 5 second periods.)
David gives perf figures of
30% - fluid_rvoice_dsp_interpolate_4th_order
27% - fluid_rvoice_buffers_mix
13% - fluid_iir_filter_apply
9% - fluid_revmodel_processmix
I ran perf (from linux-tools Debian pkg) on the RPi for nightsin.kar using two
soundfonts and got
32.07% fluid_rvoice_buffers_mix
26.89% fluid_rvoice_dsp_interpolate_4th_order
12.99% fluid_iir_filter_apply
11.00% fluid_revmodel_processmi
for the FluidR3_Gm and
29.49% fluid_rvoice_buffers_mix
23.71% fluid_rvoice_dsp_interpolate_4th_order
14.89% fluid_revmodel_processmix
12.53% fluid_iir_filter_apply
for the GeneralUser soundfont (which sounds a bit better).
No significant difference.
Jan
--
On Sun, 2012-11-18 at 08:31 -0700, Aere Greenway wrote:
> Jan & David:
>
> In my opinion, limiting the polyphony (I presume that is what you mean
> by "limiting the voices") does not adversely affect the sound.
>
> What is using up the CPU, is voices still being 'sounded' that have
> long before faded to where they are inaudible. sysstat
>
> If Fluidsynth works similarly to the EMU10K1/2 (Soundblaster & Audigy)
> chip, it should 'take-out' the oldest voices first, though I don't
> know if that is actually the case.
>
> I think the Soundblaster and Audigy soundcards have a polyphony limit
> of 64 (I have also heard that the limit is actually 48). And since
> the pieces sounded fine on my Soundblaster card, I tried setting the
> polyphony to 64, and it also sounded perfectly good, and cut down the
> processor load significantly.
>
> Trying that worked fine, with no detectable degradation in sound.
>
> Since I use Qsynth, I change this by changing the "Polyphony"
> parameter of the "Audio" tab (visible after clicking the "Setup"
> button. I do not know how to make the same change using command-line
> parameters.
>
>
> - Aere
>
> -----Original Message-----
> From: David Henningsson <di...@ubuntu.com>
> Reply-to: FluidSynth mailing list <fluid-dev@nongnu.org>
> To: FluidSynth mailing list <fluid-dev@nongnu.org>
> Subject: Re: [fluid-dev] problems with fluidsynth 1.1.6 on a raspberry
> pi
> Date: Sun, 18 Nov 2012 12:51:58 +0100
>
> On 11/18/2012 11:07 AM, Jan Newmarch wrote:
> > Thanks to Christian and Aere. Here are some more results on a file
> > nightsin.kar of various choices using pidstat:
> >
> > Version flags sound font cpu % memory % comments
> > 1.1.5 none FluidR3_GM 75% 43% unlistenable
> > 1.1.5 -z 4096 FluidR3_GM 70% 43% unlistenable
> > 1.1.5 -z 4096 GeneralUser 76% 20% unlistenable
> > 1.1.6 none FluidR3_GM 80% 40% still distorting
> > 1.1.6 -z 4096 FluidR3_GM 75% 40% distorts when
> > usage > 90%
> > 1.1.6 -z 4096 GeneralUser 65% none shown
> > distorts when usage > 90%
>
> Thanks for providing a good test case. I'm not familiar with pidstat -
> could you state the command line do you use for this, for an accurate
> comparison?
>
> It looks like the CPU % maybe does not differ that much.
>
> Actually, I recently got hold of a Nexus 7 running Ubuntu [1], which has
> a Tegra 3 core. When running NIGHTSIN.KAR (found at [2]), it does indeed
> use a lot of CPU. It runs fine for the most part, but occasionally
> breaks up. (This is with -z 4096.)
>
> Running a quick perf analysis of it, the top CPU using functions are:
>
> 30% - fluid_rvoice_dsp_interpolate_4th_order
> 27% - fluid_rvoice_buffers_mix
> 13% - fluid_iir_filter_apply
> 9% - fluid_revmodel_processmix
>
> The interpolation can be reduced, but only inside the shell it seems
> like, so that would help some (at the expense of quality, as usual).
>
> Reducing the number of voices would be the first thing to try IMO, that
> is usually not that hearable hopefully.
>
> But this is indeed an interesting optimisation problem. At least
> fluid_rvoice_buffers_mix should be able to run faster I believe. I'll do
> some experiments with it when I have some more time.
>
> // David
>
> [1] https://wiki.ubuntu.com/Nexus7
>
> [2] http://www.swissdom.cc/midis/karaoke-internacional-1/n/
>
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--
Dr Jan Newmarch
Head of ICT and Commerce (Higher Education)
P 61 3 9286 9971
M +61 4 0117 0509
F 61 3 9286 9100
W www.boxhill.edu.au
W jan.newmarch.name
E j.newma...@boxhill.edu.au
E j...@newmarch.name
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