Thanks Ian! One immediate takeaway: Interesting design, but why only 16 PCIe Gen3 lanes? That can really limit the A64fx's usefulness. Any comments from Fujitsu, and your thoughts?
My guess would be that the PCIe bus is mostly used for burst buffers (non-volatile fast storage) and system management (networking) and most of the magic happens through the Tofu in the very large system these processors are part of.
Hi TeXWiller, that was my initial thought, too. But, why limit this chip "only" to supercomputer-type machines? They did show their new chip as being superior to their SPARC64 in their talk, which is why I found this confusing, and Fujitsu needs a follow-up to their Sparc64 line ASAP, unless they have given up on the server category. However, for server use, 16 Gen3 PCIe lanes won't cut it by a mile. The A64fx design could fit the bill, and the ability to run 512 bit SIMD extensions (vs. 256 bit for current gen Sparc64) would add a strong performance boost (absolute and perf/Wh) for some key server-run applications.
They did the same thing with the K-computer: some of the HPC features that were useful for the server version were integrated into it. As to SPARC -> ARM transition, the post-K project has to show its performance and reliability, both in terms of hardware and software first. By that time the server version can be integrated with any next generation IO that is needed. That is my relatively humble opinion. ;)
They compare it to SPARC64fx, which is also supercompute-only and highly limited on the peripheral side. SPARC64 XIfx also has exactly 16 PCIe 3 lanes, just like A64FX does.
SPARC64 and SPARC64fx are not the same - SPARC64 are commercial systems running Solaris, with multithreading, SMP, and support for more than the 32GB per node of RAM present in the A64FX and SPARC64 XIfx. SPARC64 XIfx is SMP-less (multi-node is done via Tofu), has no multithreading, and has a significantly different cache configuration from SPARC64 XII (or X.)
There's a new SPARC64 on the roadmap, although I'm skeptical there will be another one after, given the decline in the commercial UNIX market.
Are they actually going to make a supercomputer in 2021 with no PCIe 4.0 and HBM3 memory? By that time both will certainly be the norm (with the final spec of PCIe 5.0 already released), so it would be very strange.
My English is not perfect. This is my favourite chip. I wish a laptop workstation with Fujitsu A64FX, with mainframe RAS. Does the 32 Gib HBM2 has ECC? And address/control parity? Does will be desktop versions? Workstation, Laptop workstation: USB C 4.0, USB A 3.1, 10-100 Gbit/s ethernet, DisplayPort, HDMI, DVI, 15 pin mini D-Sub, audio jack and digital connectors, PCI-Express 5.0/6.0, M.2, U.2, SAS, SATA, SIM, wifi, etc.
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eastcoast_pete - Wednesday, August 22, 2018 - link
Thanks Ian! One immediate takeaway: Interesting design, but why only 16 PCIe Gen3 lanes? That can really limit the A64fx's usefulness. Any comments from Fujitsu, and your thoughts?TeXWiller - Wednesday, August 22, 2018 - link
My guess would be that the PCIe bus is mostly used for burst buffers (non-volatile fast storage) and system management (networking) and most of the magic happens through the Tofu in the very large system these processors are part of.eastcoast_pete - Thursday, August 23, 2018 - link
Hi TeXWiller, that was my initial thought, too. But, why limit this chip "only" to supercomputer-type machines? They did show their new chip as being superior to their SPARC64 in their talk, which is why I found this confusing, and Fujitsu needs a follow-up to their Sparc64 line ASAP, unless they have given up on the server category. However, for server use, 16 Gen3 PCIe lanes won't cut it by a mile. The A64fx design could fit the bill, and the ability to run 512 bit SIMD extensions (vs. 256 bit for current gen Sparc64) would add a strong performance boost (absolute and perf/Wh) for some key server-run applications.TeXWiller - Thursday, August 23, 2018 - link
They did the same thing with the K-computer: some of the HPC features that were useful for the server version were integrated into it. As to SPARC -> ARM transition, the post-K project has to show its performance and reliability, both in terms of hardware and software first. By that time the server version can be integrated with any next generation IO that is needed. That is my relatively humble opinion. ;)SarahKerrigan - Saturday, August 25, 2018 - link
They compare it to SPARC64fx, which is also supercompute-only and highly limited on the peripheral side. SPARC64 XIfx also has exactly 16 PCIe 3 lanes, just like A64FX does.SPARC64 and SPARC64fx are not the same - SPARC64 are commercial systems running Solaris, with multithreading, SMP, and support for more than the 32GB per node of RAM present in the A64FX and SPARC64 XIfx. SPARC64 XIfx is SMP-less (multi-node is done via Tofu), has no multithreading, and has a significantly different cache configuration from SPARC64 XII (or X.)
There's a new SPARC64 on the roadmap, although I'm skeptical there will be another one after, given the decline in the commercial UNIX market.
Santoval - Wednesday, August 22, 2018 - link
Are they actually going to make a supercomputer in 2021 with no PCIe 4.0 and HBM3 memory? By that time both will certainly be the norm (with the final spec of PCIe 5.0 already released), so it would be very strange.SquarePeg - Wednesday, August 22, 2018 - link
08:35PM EDT - (A64FX doesn't mean Athlon 64, FX)My immediate thought when I read the title was "how the fook are they going to use that branding". Because that's what I was reminded of right away.
Nehemoth - Thursday, August 23, 2018 - link
I guess that the intended target for the product are very different from the one of AMD Athlon :)x0 - Friday, October 30, 2020 - link
My English is not perfect.This is my favourite chip. I wish a laptop workstation with Fujitsu A64FX, with mainframe RAS.
Does the 32 Gib HBM2 has ECC? And address/control parity?
Does will be desktop versions? Workstation, Laptop workstation: USB C 4.0, USB A 3.1, 10-100 Gbit/s ethernet, DisplayPort, HDMI, DVI, 15 pin mini D-Sub, audio jack and digital connectors, PCI-Express 5.0/6.0, M.2, U.2, SAS, SATA, SIM, wifi, etc.