18 Aug
2009
18 Aug
'09
5:03 a.m.
On Tuesday 18 August 2009 01:30:30 Ken Restivo wrote:
Success!
I ended up using the following flags:
-msse -msse2 -mfpmath=sse -ffast-math -fomit-frame-pointer -O3
-fno-finite-math-only -pipe
And all is well. I can run azr3, two fluidsynths, jackd, lashd,
jackminimix, linuxsampler (!), and four jack-rack instances with plugins
from CAPS, TAP, CALF, and Fons's autowah, and play them with responsiveness
and no glitches... on a dinky little Atom 1.6Ghz netbook... while compiling
software and running Firefox. Yay Linux!
Wow! I will have to try some of this stuff on the next synth I compile.
Must EVERYTHING be compiled like this or just cpu-hogs like synths?
Hardware limitations? I have a pentium-III dinosaur.
Fluidsynth through jack-rack seems a lot more responsive too; less latency,
even though latency was already quite low. The exception here is
LinuxSampler which has a little bit of a lag, understandably.
Couple issues:
1) At Fons's suggestion, I had to add "LDFLAGS += -shared -nostartfiles"
to
the debian/rules of CAPS 0.4.3 to get it to build.
2) Fluidsynth is acting very strangely. It "gets jealous". If I'm playing
another synth, which is demanding a lot of CPU, Fluidsynth throws a tantrum
and sucks up spikes of 80% CPU (according to top). AZR3 does this too
sometimes. Why is that? Why would a synth be sucking up tons of CPU even if
no MIDI data is going into it? Is it getting starved by the others.
I had this
issue with most all synths, both on Windows (I paid good cash for
them!) and on Linux. Timidity is an example.
After discussions with the authors of the Windows synths: they must be
programmed to drop resources when idle. Otherwise, their code has no way of
knowing when it is "off-line" or idle. One of them, I forget which, did this
after we discussed it.
3) Volume levels on AZR3 are sane now, for the first time ever, which
suggests maybe it had a denormal issue in there which one of those
optimization flags might have fixed.
-ken
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