I tried your patch with the [bob~] object shipped with the Windows binaries. I 
clearly get subnormals! It's actually no wonder because there isn't any 
protection against subnormals in the code (at least I couldn't spot it). 
But the weird thing is: the [bob~] I compiled myself would also show subnormals 
in your patch but the CPU load is not affected...

> Gesendet: Mittwoch, 21. September 2016 um 23:47 Uhr
> Von: katja <katjavet...@gmail.com>
> An: "Christof Ressi" <christof.re...@gmx.at>
> Cc: "pd-list@lists.iem.at" <pd-list@lists.iem.at>
> Betreff: Re: Re: Re: [PD] [bob~] denormals issue?
>
> Without -O flags you get debug-level and all function inlining is
> disabled, depending on the code it can make a huge difference indeed.
> But Pd is probably compiled with at least -O2. So the flags don't make
> much difference. The compiler? Doesn't Miller compile with MinGW
> nowadays, I don't know. MinGW brings its own standard C libs, which
> may implement math functions differently than MS. But regarding
> denormals I guess they both respect the IEEE 754 standard.
> 
> You can check if you really have subnormals using attached patch
> denorm-test.pd you. The patch tests lop~, change it to bob~.
> 
> On Wed, Sep 21, 2016 at 11:18 PM, Christof Ressi <christof.re...@gmx.at> 
> wrote:
> > the SSE optimizations don't seem to matter at all. skipping -ffast-math 
> > gives a slight overall CPU rise, while skipping -O3 gives me huge CPU rise 
> > (20 bob~ filters are already to much for one core). Even when skipping all 
> > of those flags, the denormals issue is still not present.
> >
> > Maybe it has something to do with the compiler?
> >
> >> Gesendet: Mittwoch, 21. September 2016 um 22:47 Uhr
> >> Von: katja <katjavet...@gmail.com>
> >> An: "Christof Ressi" <christof.re...@gmx.at>, "pd-list@lists.iem.at" 
> >> <pd-list@lists.iem.at>
> >> Betreff: Re: Re: [PD] [bob~] denormals issue?
> >>
> >> I'm curious to know if the flags do flush denormals on your processor.
> >> Forgot to mention that '-O3 -ffast-math' are also set,
> >> platform-independent. So if you have a chance to try which flag does
> >> something... It's just curiosity.
> >>
> >> On Wed, Sep 21, 2016 at 10:34 PM, Christof Ressi <christof.re...@gmx.at> 
> >> wrote:
> >> > Hi Katja,
> >> >
> >> >> Even if your test reveals a beneficial effect from compiler flags,
> >> >> it is better when denormals are detected and flushed in the C code.
> >> >
> >> > definitely! Maybe using the PD_BIGORSMALL macro on each filter state at 
> >> > the end of the DSP routine does the trick, just like in all the other 
> >> > recursive filters in Pd.
> >> >
> >> >
> >> >
> >> >> Von: katja <katjavet...@gmail.com>
> >> >> An: "Christof Ressi" <christof.re...@gmx.at>
> >> >> Cc: pd-list <pd-l...@iem.at>, "Miller Puckette" <m...@ucsd.edu>
> >> >> Betreff: Re: [PD] [bob~] denormals issue?
> >> >>
> >> >> Hi Christof,
> >> >>
> >> >> Makefile.pdlibbuilder passes flags '-march=pentium4 -msse -msse2
> >> >> -mfpmath=sse' for optimization to the compiler on Windows. You could
> >> >> try compiling without (some of) these flags to see if they are
> >> >> responsible for the different behavior. Makefile-defined optimization
> >> >> flags can be overriden with argument CFLAGS given on command line.
> >> >>
> >> >> The effect of optimization flags on denormals varies per processor
> >> >> type, unfortunately. When we had denormals on Raspberry Pi ARMv6 they
> >> >> wouldn't go away no matter what flags, is what I remember. Even if
> >> >> your test reveals a beneficial effect from compiler flags, it is
> >> >> better when denormals are detected and flushed in the C code. Anyway,
> >> >> it is still interesting to know what makes the difference.
> >> >>
> >> >> Katja
> >> >>
> >> >> On Wed, Sep 21, 2016 at 12:32 AM, Christof Ressi 
> >> >> <christof.re...@gmx.at> wrote:
> >> >> > Hmmm... I compiled [bob~] myself with MinGW and pd-lib-builder and I 
> >> >> > noticed two things:
> >> >> > 1) the CPU rise is gone
> >> >> > 2) it needs only half the CPU. I put 20 [bob~] objects in a switched 
> >> >> > subpatch and measured the CPU load. The DLL which comes with the 
> >> >> > Windows binaries needs 15%, while my own DLL needs only 7%! That's 
> >> >> > quite a deal...
> >> >> >
> >> >> > Christof
> >> >> >
> >> >> > PS: I attached the DLL in case you wanna try it yourself.
> >> >> >
> >> >> >
> >> >> >> Gesendet: Samstag, 17. September 2016 um 22:58 Uhr
> >> >> >> Von: "Christof Ressi" <christof.re...@gmx.at>
> >> >> >> An: pd-l...@iem.at, "Miller Puckette" <m...@ucsd.edu>
> >> >> >> Betreff: [PD] [bob~] denormals issue?
> >> >> >>
> >> >> >> Hi Miller,
> >> >> >>
> >> >> >> feeding audio into [bob~] and then going to zero will increase the 
> >> >> >> CPU load by ca. 6%. Clearing the filter or adding a tiny amount of 
> >> >> >> noise brings the CPU load back to its usual level immediately, so I 
> >> >> >> guess it's a problem with denormals.
> >> >> >> My Pd load meter won't really show the increase, but it's clearly 
> >> >> >> visibly on Process Explorer.
> >> >> >>
> >> >> >> See my attached patch. Tried with Pd 0.47.1, Lenovo Thinkpad L440, 
> >> >> >> Windows 7.
> >> >> >>
> >> >> >> Christof_______________________________________________
> >> >> >> Pd-list@lists.iem.at mailing list
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> >> >> >>
> >> >> > _______________________________________________
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> >> >> >
> >> >>
> >>
> 

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