Phase 3 System Online

We are pleased to be able to tell you that the first part of the phase 3 upgrade is complete. The HECToR system is now made up of AMD 'Interlagos' Opteron Processors with the 'Bulldozer' architecture.

There are currently 1856 nodes (59,392 cores).

All users should recompile their codes for the phase 3 system.

Key changes

The key changes on the shift from phase 2b to phase 3 are:

  • There are 32 cores per node. aprun option -N can take values from 1 to 32.
  • There are 8 cores per NUMA region. aprun option -S can take values from 1 to 8.
  • mppwidth PBS option should now usually be a multiple of 32.
  • mppnppn PBS option should now usually be 32.
  • Maximum queue size is currently 1024 nodes (32,768 cores).
  • Default compiler suite is now Cray instead of PGI.
  • Usage unit in SAFE is now kAU (1 kAU = 1000 AU).


A number of documents on the HECToR website provide useful information on the phase 3 system.

CrayXE Best Practice Guide
As part of the PRACE intiative, EPCC and KTH staff have written a "Best Practice" guide for Cray XE systems which contains a lot of information that HECToR users will find useful. The version on the HECToR website has been adapted to specifically focus on HECToR phase 3 and contains information useful for running and optimising codes for the phase 3 system. The guide contains detailed information on the new phase 3 hardware and how it may impact your simulations. Also included is information on profiling and debugging your code to get the maximum performance out of the system. We recommend that all users take a look at this document to understand the changes for phase 3. This is the initial version of this document and it will continue to be developed.

HECToR User Guide
The HECToR User Guide has been updated to reflect the phase 3 system. The guide contains information about the phase 3 hardware and other useful information; including example phase 3 job submission scripts.

Default software versions on Phase 3
This page on the website details the default software versions of compilers, tools, libraries and centrally supported third-party software on the phase 3 system.

Phase 3 Good Practice Guide
HECToR CSE staff have also written a good practice guide to the phase 3 system that includes useful technical information on the Bulldozer architecture and how to get the best out of the hardware.

As always, if you have any questions or require help, please do not hesitate to contact the HECToR Helpdesk.