[Bug libgomp/37586] OpenMP thinks that I have 1 processor on an 8 processor pc

["rrpeter at sandia dot gov" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #8 from rrpeter at sandia dot gov  2008-10-13 15:17 -------
Subject: Re:  OpenMP thinks that I have 1 processor
 on an 8 processor pc

jakub at gcc dot gnu dot org wrote:
> ------- Comment #7 from jakub at gcc dot gnu dot org  2008-10-13 09:43 -------
>  sched_getaffinity(3502, 128,  { ff, 0, 0, 0 }) = 32
>  ....
>   sched_getaffinity(3502, 128,  { 1, 0, 0, 0 }) = 32
>  ...
>  sched_getaffinity(3502, 128,  { 1, 0, 0, 0 }) = 32
> Shows that the process originally was bound to any of the 8 CPUs (mask 0xff),
> but
> after a while it got confined only to the first CPU.  The question is what
> has done that.  You can look for sched_setaffinity syscall in the strace dump,
> then either from the surrounding syscalls or under debugger find out where
> sched_setaffinity or pthread_setaffinity_np functions have been called from
> or if the program invokes the syscall directly, without calling a
> libc/libpthread function.
>
>
> --
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37586
>
> ------- You are receiving this mail because: -------
> You reported the bug, or are watching the reporter.
>
>   
Hi Jakub,

I did as you asked and get:
sched_setaffinity(24094, 128,  { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0 }) = 0


Its buried in other "startup" code:
...................
NOTE: usg::Scene using usg default data file path list
      path = 
.:/usr/local/share/OpenSceneGraph/data:/usr/local/share/OpenSceneGraph/data/Env:/usr/local/share/OpenSceneGraph/data/fonts:/usr/local/share/OpenSceneGraph/data/Images:/usr/share/OpenSceneGraph/data:/usr/share/OpenSceneGraph/data/Env:/usr/share/OpenSceneGraph/data/fonts:/usr/share/OpenSceneGraph/data/Images
camera number: 0
sched_setaffinity(24094, 128,  { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0 }) = 0
INFO> navigation mode set to umbra
Warning: font file "fonts/arial.ttf" not found.
Setting savConfigCB to '::guiWrapper saveConfig'
sLoadFile  filename:/home/vision_data/geometry_objects/test.cdf  
fileType:  lineRowCnt=-1  lineColCnt=-1
std::string UmbModCDFDataSet::LoadFile(const s......
...................................

I suppose that this means that something in Tcl, OpenScenegraph, umbra, 
my own rwm is setting the following software to run on only one 
processor.  I ran a strace -f to get a full "dump" and found that it 
occurs between 2 "open(library)" calls.  I backtracked to OpenSceneGraph 
to find one possibility:

[hopper@babs src]$ pwd
/usr/local/src/OpenSceneGraph-2.4.0/src
[hopper@babs src]$ find . -exec grep -n -H sched_setaffinity {} \;
./OpenThreads/pthreads/CMakeLists.txt:73:  sched_setaffinity( 0, 
sizeof(cpumask), &cpumask );
./OpenThreads/pthreads/CMakeLists.txt:83:  sched_setaffinity( 0, &cpumask );
./OpenThreads/pthreads/PThread.c++:135:            sched_setaffinity( 0, 
sizeof(cpumask), &cpumask );
./OpenThreads/pthreads/PThread.c++:137:            sched_setaffinity( 0, 
&cpumask );
./OpenThreads/pthreads/PThread.c++:549:        sched_setaffinity( 0, 
sizeof(cpumask), &cpumask );
./OpenThreads/pthreads/PThread.c++:551:        sched_setaffinity( 0, 
&cpumask );
./OpenThreads/pthreads/PThread.c++:984:        sched_setaffinity( 0, 
sizeof(cpumask), &cpumask );
./OpenThreads/pthreads/PThread.c++:986:        sched_setaffinity( 0, 
&cpumask );
./OpenThreads/pthreads/GNUmakefile:43:ifeq 
($(COMPILE_USING_TWO_PARAM_sched_setaffinity),yes)
./OpenThreads/pthreads/GNUmakefile:44:DEF += 
-DCOMPILE_USING_TWO_PARAM_sched_setaffinity
[hopper@babs src]$

This looks like a possibility for the source of my problem or not?

Can I make my own call to sched_setaffinity?  There is, of course, 
always the possibility of causing problems.

Ralph


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37586