Cray, AMD to Extend DOE’s Exascale Frontier

Re:Cray, AMD to Extend DOE’s Exascale Frontier by berbec on Tuesday May 07, 2019 @09:24AM (#19849083)

What's the advantages of infinity fabric over pcie 4 for cpu/gpu?

What interconnects do these sorts of machines use? I assume even 100GbE isn't enough?

Just curious. It's interesting what exists in the "so far beyond my price range as to be ludicrous" category.

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Re:Cray, AMD to Extend DOE’s Exascale Frontier by Symmetry on Tuesday May 07, 2019 @09:27AM (#19849102)

PCIe provides communication but isn't intended to provide memory coherency. There's a lot of work that goes on in figuring out which cache(s) have a copy of which cache line and figuring out how to resolve conflicting access needs.

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Re:Cray, AMD to Extend DOE’s Exascale Frontier by gnode on Tuesday May 07, 2019 @09:30AM (#19849115)

Infinity Fabric / HyperTransport is generally lower level and lower latency than PCIe. It's aimed more for use as a front-side bus than a peripheral interconnect. A better analogue would be Intel's QuickPath Interconnect.

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Re:Cray, AMD to Extend DOE’s Exascale Frontier by Grazester on Tuesday May 07, 2019 @09:34AM (#19849138)

As to the interconnect question. They usually use InfiniBand but Cray uses their proprietary interconnect tech.

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