[PD] Hunting denormals?

Andy Farnell padawan12 at obiwannabe.co.uk
Fri Oct 31 21:59:23 CET 2008

A useful debug trick, to make sure denornals are the problem,
is to inject a wee bit of noise into the path and see if it
speeds up. My experiences of them in the past is that they
take a while st show up, maybe many seconds or even minutes
after the patch seems silent (rather than being present under
quiescent conditions).

On Fri, 31 Oct 2008 16:27:08 -0400
Bill Gribble <grib at billgribble.com> wrote:

> I have a patch of medium complexity, with a handful of instruments~ and
> a bunch of sequencing and arranging-type message handling.  On my speedy
> Intel laptop it has no problem and barely notches the CPU usage.
> However, when I run this patch on my teeny Geode-based UMPC it pegs CPU
> at 100%. 
> I'm pretty sure this is a denormal issue.  There are a grand total of
> maybe 5 noise~, 5 osc~, 10 vline~, 5 lop~, and 1 delay line in the whole
> patch and not much else besides message processing... I wouldn't guess
> this to run me out of compute power. 
> Any hints on how to isolate where the denormals might be popping up?  I
> have looked for signal processing loops, and the only ones I create are
> around the delayline (feedback) and I suppose in the iir implementation
> of the lop~.  
> Any help appreciated, 
> Bill Gribble
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Use the source

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