From: Richard Gerber (ragerber_at_lbl_dot_gov)
Date: 05/15/2006
Dear NERSC Users,
Bassi is currently up and running AIX 5.3. NERSC is addressing some
minor issues
resulting from the recent OS migration and they are expected to be
resolved soon.
There are a few items you should be aware of:
* The compute nodes now have 24 GB of memory devoted to large pages. If
you see
unexpected changes in your code's performance, please make sure it
is large-page
enabled. Use "checklp a.out" to check if an executable named "a.out"
is large-page
enabled. If it is not, relink with the "-blpdata" flag or use
"ldedit -blpdata a.out" to
enable a.out to use large pages. There is very little memory
available (only a few GB
per node) for applications that use only small-page memory.
* A bug has been identified that can cause hangs or very slow startup of
parallel programs
that read from Standard Input (STDIN). If your program reads from
STDIN, but only
needs that information in a single MPI task, set the environment
variable
MP_STDINMODE to the value of that task number. For example, if STDIN
only needs to be
read from task 0 (zero), before you execute your code set
MP_STDINMODE to have
the value 0 (zero).
* LAPI one-sided functions may not be supported using RDMA in the
current version
of LoadLeveler.
* SMT is available on the POWER 5 under AIX 5.3, but it is not currently
enabled. NERSC
will evaluating SMT on Bassi in the coming weeks.
Thank you to those have reported problems. Please report any problems to
consult_at_nersc_dot_gov.
Richard Gerber