hwloc support in cp2k-trunk

Axel akoh... at gmail.com
Fri Jan 20 22:48:52 CET 2012


hi everybody,

can somebody give me some pointers to debug
the hwloc/libnuma support in the current cp2k trunk?

it appears that libnuma support is not (yet) functioning,
even after i fixed a trivial bug in the C language wrapper.

[install at master makefiles]$ svn diff machine 
Index: machine/ma_linux.c
===================================================================
--- machine/ma_linux.c       (revision 12108)
+++ machine/ma_linux.c       (working copy)
@@ -51,7 +51,7 @@
 
   //libnuma has no support for I/O devices
   topo->nnetcards = 0;
-  local->nnetcards = 0;
+  local_topo->nnetcards = 0;
 
   topo->nsockets = linux_get_nsockets();
   local_topo->nsockets = topo->nsockets;


it also seems that hwloc requires a somewhat recent version
of the hwloc package. RHEL-6.x ships with 1.1 which
is missing some defines but using a self-compiled hwloc-1.3.1 
resulted in a working executable.

however, when playing with the options i see some
inconsistencies, especially when looking at the MPI task
and thread placement lists for a cp2k.psmp binary.

i currently use shell script based on numactl to schedule
the MPI task to processor/memory and thread assignments
and the performance data confirms it to be correct. however,
the corresponding output from the MACHINE_ARCH flags
is inconsistent with that. like all MPI tasks seem to be
located on the same physical node (which is not true)
and thread assignments are "crazy" as well.

i would very much appreciate it, somebody could
tell me how much this is still work in progress and 
on what platforms, this has been tested, and who
would be person to communicate patches, or ideas
for modifications or debug info to.

thanks in advance,
     axel.
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