Lightweight kernel operating system: Difference between revisions

Revision as of 14:14, 31 March 2012

Revision as of 14:39, 8 April 2012

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A [[massively parallel]], [[high-performance computing]] (HPC) system is particularly sensitive to [[operating system]] overhead. Traditional, multi-purpose, operating systems are designed to support a wide range of usage models and requirements. To support the range of needs, a large number of system processes are provided and are often inter-dependent on each other. The computing overhead of these processes leads to an unpredictable amount of processor time available to a parallel application. A very common [[parallel programming model]] is referred to as the [[bulk synchronous parallel]] model which often employs [[MPIMessage Passing Interface]]{{dn|date=March 2012}}(MPI) for communication. The synchronization events are made at specific points in the application code. If one processor takes longer to reach that point than all the other processors, everyone must wait. The overall finish time is increased. Unpredictable operating system overhead is one significant reason a processor might take longer to reach the synchronization point than the others.

Custom '''Lightweight Kernel''' (LWK) operating systems, currently used on some of the fastest computers in the world, help alleviate this problem. The [[IBM]] [[Blue Gene]] line of [[supercomputers]] runs various versions of [[CNK operating system]].<ref name=bgl-cnk>{{cite journal