Complementary Capability Computing on HPCx

Dr Alan Gray

212th November 2008 HPCx User Group Meeting

HPCx and HECToR: complementary services

312th November 2008 HPCx User Group Meeting

Complementary capability computing

• Complementary services provide a unique opportunity to maximise the benefits for UK research– HECToR is our leading HPC facility – HPCx is our "National Supercomputer", trading

overall utilisation in favour of a more flexible servic

• The main principles behind providing complementary services are:– to maximise the combined research benefits of

HECToR and HPCx for the UK HPC user community; – to ensure that the most appropriate service is

chosen for the scientific research to be conducted.

412th November 2008 HPCx User Group Meeting

HPCx: a more flexible service

• HPCx’s operation has been modified to provide a more flexible service– We have adapted policies and enabled new

features and functionalities• HPCx can handle more unusual jobs

– e.g. jobs that cannot easily or readily be accommodated on HECToR

• Certain job classes have adverse impact on overall utilisation on prime national service– but can be accommodated on a complementary

service• HPCx users have helped to guide these changes

– We visited all consortia with >= 1M AUs remaining

512th November 2008 HPCx User Group Meeting

HPCx flexibility

612th November 2008 HPCx User Group Meeting

Flexible Policies

• Very long jobs– HPCx now has 48 hour queues, requests for

longer jobs will also be considered

• Interactive and responsive computing– HPCx now has short high priority 20 minute

debug queues– HPCx can now accommodate more flexible

access patterns, for example to exploit grid technologies

712th November 2008 HPCx User Group Meeting

New Features and Functionality

• Advanced reservation– HPCx now supports the Highly Available Robust

Co-scheduler (HARC) – Allows users to reserve processors for a

particular time in the future – Relevant for meta-computing, computational

steering and on-line visualisation – You may just wish to reserve a series of

processors one afternoon

812th November 2008 HPCx User Group Meeting

New Features and Functionality

• Ensembles of jobs – We have developed functionality which allows

multiple independent jobs to be easily submitted from the same job script to run simultaneously

• Visualisation– Paraview parallel visualisation tool now installed

• Computational steering– We are working directly with consortia to enable

this for their specific cases

912th November 2008 HPCx User Group Meeting

Additional flexibility

• Shared memory– A cluster of fat shared-memory nodes

• each with several processors under the control of a single operating system

– Advantageous for applications that exploit shared memory parallelism and for users with large memory jobs

– Accessing the full memory • Under populating the node • Shared memory segments and shared memory

parallelism

1012th November 2008 HPCx User Group Meeting

Additional flexibility

• Large memory jobs– Phase 4 upgrade of HPCx – Two of the IBM 575+ servers will have 128 GB

of memory

• Data intensive jobs– HPCx has a significant tape store– Ideally suited for users with a need to archive

large amounts of data to tape for local processing

1112th November 2008 HPCx User Group Meeting

How to exploit HPCx’s new flexibility

• For the remainder of HPCx, we will (in addition to running the helpdesk) focus our additional support on Complementarity– In particular we will support the new CCC projects

in any way we can• Please get in touch with the helpdesk with

– questions– suggestions or requests– requirements that cannot easily be met within the

current operational policies of HECToR and HPCx – feedback

• Guidelines on Complementarity are available at:– http://www.hpcx.ac.uk/support/complementarity/