Hi,
>Le 26/04/2016 17:34, Element Green a écrit :
>Actually that is not true, in regards to FluidSynth utilizing multiple
CPUs. It can do exactly that, you just have to tell it to by setting
synth.cpu-cores. It seems those Raspberry Pi boards have quad cores?
So you could pass "-o >synth.cpu-cores=4".
Just to confirm that "synth.cpu-cores" setting work well. This has been
verified on others boards (unfortnately not yet on Raspberry Pi boards !).
Examples of performance measurement follows below:
1) Pentium(R) 4 CPU 1.70 Ghz (1 core): fluidsynth can play 218 voices
(100 % cpu)
2) Pentium(R) 4 CPU 2.40 Ghz (1 core): fluidsynth can play 336 voices
(100 % cpu)
3.1) AMD Phenom II x 4 955 (4 core): fluidsynth (synth.cpu-cores=1) can
play 745 voices (100 % cpu)
3.2) AMD Phenom II x 4 955 (4 core): fluidsynth (synth.cpu-cores=2) can
play 1491 voices (100 % cpu)
3.3) AMD Phenom II x 4 955 (4 core): fluidsynth (synth.cpu-cores=3) can
play 2319voices (100 % cpu)
3.4) AMD Phenom II x 4 955 (4 core): fluidsynth (synth.cpu-cores=4) can
play 3015voices (100 % cpu)
Performance measurement has be done with this patch:
http://lists.nongnu.org/archive/html/fluid-dev/2016-02/msg00009.html
It worth to extract "performance measurement" for others boards
(Raspberry ,...) and share theses informations.
>Le 26/04/2016 17:34, Element Green a écrit :
>So you may want to make sure that FluidSynth is actually built with
hardware floating point support.
That is true that compilers options are important !
As an example for the same hardware (point (2) above: Pentium(R) 4 CPU
2.40 Ghz)
- (a) using VS studio 6 and running on Windows XP: fluidSynth can play
336 voices max.
- (b) using gcc and running on linux Debian: fluidSynth can play
264voices max.
Actually i don't know why case (b) is 21 % less performant than case (a)
but i suspect compilers options.
Best regards,
Le 26/04/2016 17:34, Element Green a écrit :
Just wanted to follow up with some info on FPU support for that
system. It sounds like the Raspberry Pi does have hardware FPU
support. However, it may be that FluidSynth has not been compiled
with it. From the 2nd stackexchange answer
(http://raspberrypi.stackexchange.com/questions/545/does-the-raspberry-pi-have-hardware-floating-point-support)
I found the following CFLAGS mentioned for this:
-mcpu=arm1176jzf-s -mfpu=vfp -mfloat-abi=hard
So you may want to make sure that FluidSynth is actually built with
hardware floating point support.
Best regards,
Element
On Tue, Apr 26, 2016 at 9:17 AM, Element Green
<elem...@elementsofsound.org <mailto:elem...@elementsofsound.org>> wrote:
Hello,
On Tue, Apr 26, 2016 at 2:25 AM, R.L. Horn <li...@eastcheap.org
<mailto:li...@eastcheap.org>> wrote:
On Fri, 22 Apr 2016, Maciej - filologia angielska wrote:
2. Today I noticed that the problem must be due to
Raspberry Pi's limitations in terms of its computing power.
Fluidsynth, it has to be said, is a bit of a CPU hog.
Unfortunately, I believe the only way to boost performance is
by using boards with more processors, which fluidsynth doesn't
take advantage of.
Actually that is not true, in regards to FluidSynth utilizing
multiple CPUs. It can do exactly that, you just have to tell it
to by setting synth.cpu-cores. It seems those Raspberry Pi boards
have quad cores? So you could pass "-o synth.cpu-cores=4".
However, from a quick glance of the specs of those boards, it
isn't apparent as to whether it has an FPU. If it does not have
an FPU then you will get horrible performance, since all the
floating point math that FluidSynth is based on will be emulated
in software.
fluidsynth -C0 -R0 -r22050 -l -a alsa -o
audio.alsa.device=plughw:0
An HW: device would probably be faster (at least you don't
have resamplers on top of resamplers), but latency is often a
problem.
Then I increased the -r to 44100 and subsequently to
48000. With each increase, the Rpi would encounter "funny
noises/drop-outs" (I do not know how to call them) and
eventually the machine would crash during some of the more
complex parts of the MID song.
That's not supposed to happen: you shouldn't get an EIO unless
something really serious goes wrong. It sort of sounds like
the driver simply gives up after X number of under-runs.
I suspect the same thing. Something is likely wrong with the
driver in regards to underruns.
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Best regards,
Element Green
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