SuperMUC PetaFlop System: Status and schedule for start of user operation

LRZ aktuell publish at
Mo Jun 4 17:17:07 CEST 2012

Dear users of the national supercomputing facilities at LRZ,
 With the installation of the new three Petaflop/s system "SuperMUC" by
 IBM nearing its completion, we are now starting to prepare for user
 operation of the system. The LINPACK benchmark has been successfully
 run, and the results will soon be published at the International
 Supercomputing Conference (ISC12) in Hamburg; people participating in
 ISC are cordially invited to the Gauss Centre s booth, where further
 information will be forthcoming. Also, LRZ s director Prof. Arndt Bode
 will be speaker of a keynote talk at ISC12, an important topic of which
 will be the innovations that were developed to enable energy efficient
 usage of SuperMUC.
 ISC12 event calendar
   * Monday 9:00 ISC Opening session with 39th TOP500 list
   * Thursday 12:00 keynote talk by Prof. Bode on extreme energy
   * Gauss Centre for Supercomputing workshops
 The Gauss Centre's booth at ISC12 has the number 150.
 Starting user operation
 It is presently expected that initial user operation with users
 selected from large-scale projects will start at the end of June or the
 beginning of July. These users will be contacted by LRZ approximately
 one week in advance of being authorized for access. Some time later,
 LRZ will proceed to ramp up usage until regular user operation will be
 reached approximately in mid-August.
 Limitations of early user operation
 We expect that during early user operation we still need to flush out
 glitches. Therefore, early users must expect unannounced or very
 short-term scheduled maintenances. Early users are encouraged to report
 any observed problems via the LRZ service desk.
 Differences between SuperMIG and SuperMUC usage
   * Node architecture: SuperMUC is comprised of 16-way Sandy Bridge
     nodes; these are equipped with 32 GBytes of main memory   much less
     than the SuperMIG nodes. Due to OS requirements, probably 26 GBytes
     per node will be available in user space. LRZ will also allow usage
     of logical hardware threads (SMT/Hyperthreads, enabling use of up
     to 32 tasks per node), however this resource is also partially used
     by OS services, and it is very much application dependent whether
     any performance improvement can be derived from use of SMT.
   * Code compatibility: It is recommended to rebuild separate
     executables for use on SuperMUC. While the compilers and basic
     libraries will be the same as on SuperMIG, the new architecture
     supports additional instructions (AVX SIMD extension), and IBM has
     implemented a major new version of the parallel environment
     (including the MPI library). Both of these may inhibit backward
     compatibility, and we d like to avoid having to deal with a lot of
     incidents reporting such (not really solvable) compatibility
   * File systems: The file systems pointed to by the $SCRATCH and $WORK
     environment variables will be the new, and vastly larger and
     better-performing GPFS file systems. The HOME file system will be
     still shared between SuperMIG and SuperMUC. We will provide
     additional information on how to transfer data between the
     non-shared SuperMIG and SuperMUC file systems via the file system
 The LRZ SuperMUC web page will be updated to reflect the changes
 discussed above. In particular the new LoadLeveler job classes and the 
 file systems will be documented; it may take some time before other
 parts of the documentation are complete.
 If you are interested in an introduction on how to use the features and
 software of the new system, please register for the course 
 "Introduction to SuperMUC" scheduled for the week starting July 2.
 Specialists from Intel and IBM have been invited to do presentations at
 this event.

 This information is also available on our web server

 Reinhold Bader

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