Gem sucking whole CPU for no visible reason... intermitently WAS Re: [GEM-dev] Re: [PD-dev] oprofile - streamlining Pd/gem patch

Mathieu Bouchard matju at artengine.ca
Thu May 18 18:52:11 CEST 2006


On Wed, 17 May 2006, B. Bogart wrote:

> B: what the heck "zero" is and why its using 12% CPU

The names you see below are most likely the names of memory segments,
which are normally filenames. One way to allocate memory is to mmap the
"/dev/zero" file in MAP_PRIVATE mode. If the program-counter is caught
sitting in such an area, it means that there might be something like
runtime-generated code being run, or that some drivers are loaded in an
unusual way, e.g. read() the executable into some malloc()ed or mmap()ed
area...

note that malloc may use mmap, and in fact does, for blocks of 128k and 
more.

also note that since a few years, XFree86 and XOrg do not use the OS's
dynamic-loader, in order to support more non-UNIX systems. (well that's
what I heard). So I suspect that "zero" is the non-GL portion of the 
nVidia driver.

 _ _ __ ___ _____ ________ _____________ _____________________ ...
| Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju
| Freelance Digital Arts Engineer, Montréal QC Canada




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