[PD] denormals from [cyclone/svf~] on Linux 64 bit

Hans-Christoph Steiner hans at at.or.at
Tue Feb 26 23:39:50 CET 2013

I, for one, am very happy that you post on denormal issues!  Its great to have
these hard technical details worked out so that they don't trip us up in
future works :)

On my Linux Mint Maya 64-bit machine, I get about 3% CPU before it hits the
denormal, then about 11% CPU.  Hitting 1 jumps it back down to 3%.

Is it worth trying bsaylor/svf~?  I don't know if it works better in this
situation.  I don't think cyclone has gotten many 64-bit fixes.  As part of
the Pd-extended 0.43.4 release, I did do a push to fix a lot of 64-bit issues
related to GUI stuff, but there are still a number of cyclone objects that do
not have proper 64-bit array support.


On 02/26/2013 04:26 PM, katja wrote:
> Since last week I have my own Linux 64 bit machine. One of the first
> issues with Pd-extended on this machine was a strongly increased CPU
> load when audio input is temporarily shut off from parts of my patch.
> Subnormals! After three hours of puzzling I identified at least one
> offender: [cyclone/svf~].
> Sorry that most of my posts to this list seem to be about subnormals.
> That's quite boring. But they're seriously hogging my CPU time like a
> swarm of grasshoppers. As I got this 64 bit machine so recently I
> don't know if the issue with [cyclone/svf~] exists in earlier Pd-E
> versions. Also, I can not understand why it happens, because the
> object is protected against subnormals with function PD_BIGORSMALL().
> This works well on all my other systems. Moreover, it works well for
> other feedback delay objects like [lop~] on Linux 64 bit.
> I'd like to know if anyone can confirm the issue. I was planning to do
> my own state variable filter anyway, but it would be nice to have a
> working [cyclone/svf~] as well. Check the object with attached patch
> if you can. To be specific, I have the issue with Pd-E 0.43.4 for
> Debian Squeeze amd64 from nightly builds. The i386 build is not
> affected.
> Katja
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