Crisis in HPC Personal Comment - Tom Lake, GLOSSA & InterGlossa Ltd.

Thanks for organising the `Crisis in HPC' meeting - it was very enjoyable. I think that there are some serious points coming out of it.

Large machine and small machines

The T3D can achieve top power with a relatively small number of processors using leading edge processors and interconnect. This means that problems don't have to be TOO large to use it well.

Machines using less tricky technology might be more cost-effective but would would need relatively larger problems to be used well because they had more processors to achieve a given power.

Funding committees might consider buying more cost-effective, better quality (low g,l) machines at lower single node power.

BSP

I was suprised to hear everyone talking about the shared memory library and little use of the BSP ideas on the T3D. Can this really be the situation.

Your dream machine

There are a lot of intermediate stages between where we are today and the full virtual shared memory story as I am sure you are aware. I think it won't be possible to throw away the advantages of scheduling the thread where the private data is already loaded for a long time.

How does your machine actually deal with cache coherence of channels? Is this a special protocol? It would be harder in C with channels because of the uncertainty over type.

Regards,
Tom Lake

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Parallel Processing and Research Consultants | GLOSSA & InterGlossa Ltd  
Email:  Tom.Lake@glossa.co.uk                | 59, Alexandra Road
Fax:    +44 1734 561919                      | Reading   RG1 5PG
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