[PD] ICC compile [or: PD + P4 + Linux = massive headache!]

derek holzer derek at x-i.net
Fri May 7 11:51:01 CEST 2004

Hi Tim,

Tim Blechmann wrote:

> i'm not completely shure how icc for ia32 can handle denormals ... their
> 64bit compiler has a flag to flush denormals to zero, but not the ia32
> compiler...

What are the maintainers of the windoze packages of PD using to compile? 
Whatever it is, it seems to clear up any denormal or CPU spike problems.

> well, there is pd's PD_BADFLOAT macro that _should_ to that, too, but
> this has only effect if the nubers are already denormal, so maybe it's
> a good idea to reset the value to flush every number a 24 / 32 bit dac
> would consider to be zero to zero...

Can you tell me a bit more about this? How and where should I start with 

I have found that certain objects have *stong* denormal tendencies, 
including hip~, lp~, np~, throw~, catch~ and probably more that I 
haven't weeded out yet.

The bottom line is that patches which are completely fine to run on 
windoze and on most AMD processors with Linux completely screw up my P4 
laptop. We are talking grinding halts of DSP, sudden [+ lasting!] leaps 
of CPU usage over 100% and even completely freezing the machine if I 
happen to be in realtime mode. Not pretty.

This has made me very careful about my patches these days, and while it 
has improved my patching technique immensely ;-), it is still a real 
problem when I am the only one getting errors with my own patches, and 
everyone else who tests them in a different environment has none at all.

I've written this list about it several times now, but I am not a C 
programmer, so there are only limited things which I can do [besides 
buying a new laptop or switching back to winschnoz]. Trying to recompile 
with a different compiler is one of them.

> if you are using the current devel branch from cvs, just configure with
> --enable-icc --enable-optimize=pentium4 ... i didn't wanted to edit my
> makefiles every time...

Using "./configure --enable-icc --enable-optimize=pentium4 
--enable-jack --enable-fftw" still uses GCC. Using "CC=icc CXX=icc" 
tells it to use ICC, but I get an error that the C compiler cannot 
create executables. I have a hunch that this is because I still haven't 
gotten this ridiculous key ["It should arrive within one business day", 
sez Intel...]

I [heart] computers.

derek holzer ::: http://www.umatic.nl
---Oblique Strategy # 6:
"Abandon normal instruments"

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