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Show HN: Turing Pi 2 – a compact ARM cluster with 32 GB RAM

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Re: Show HN: Turing Pi 2 – a compact ARM cluster with 32 GB RAM

#11

Post by geerlingguy »

nsky-world wrote: post #6
geerlingguy wrote: post #4

Earlier quoted context omitted.

For the mini PCIe, do you mean they will be PCIe 1x slots, or something like an M.2 connector? And will it be set up where each board gets one of those slots (e.g. 2 boards get single PCIe, 2 boards get single SATA)?

m2 connector is something we are still experimenting with. The first two nodes are exposed to mini PCI express port, the third node is exposed to 2-ports 6 Gbps SATA controller. You can use the network file system within the cluster to access hard drives from other nodes.

I guess it's possible to adapt the mini PCI express port to M.2 pretty easily too. Having it PCI express lets you do other interesting things though too besides just storage.

Re: Show HN: Turing Pi 2 – a compact ARM cluster with 32 GB RAM

#12

Post by geerlingguy »

rektide wrote: post #7
nsky-world wrote: post #2

Today we are thrilled to announce the Turing Pi V2. The Turing Pi V2 is s compact cluster in a mini ITX form factor with 4 x cluster nodes, 2x mini PCIe (Gen 2) ports, 2x SATA (Gen 3) ports, and new Raspberry Pi compute modules 4 support. The Turing Pi 2 cluster is architecturally similar to the AWS Graviton clusters. The CM4 processor uses the ARMv8 architecture. You can build images and applications for AWS instanc…

> The Turing Pi 2 cluster is architecturally identical to the AWS Graviton clusters. Graviton2 uses Armv8.2-A, as opposed to the Armv8.0-A on the CM4. Graviton2's cores are "Neoverse" vs CM4's Cortex A73, which is also a significant difference. A lot of code will be portable, but these are significantly different cores.

Probably more accurate to put "architecturally similar".

Re: Show HN: Turing Pi 2 – a compact ARM cluster with 32 GB RAM

#14

Post by nsky-world »

geerlingguy wrote: post #12
rektide wrote: post #7

Earlier quoted context omitted.

> The Turing Pi 2 cluster is architecturally identical to the AWS Graviton clusters. Graviton2 uses Armv8.2-A, as opposed to the Armv8.0-A on the CM4. Graviton2's cores are "Neoverse" vs CM4's Cortex A73, which is also a significant difference. A lot of code will be portable, but these are significantly different cores.

Probably more accurate to put "architecturally similar".

Noted!

Re: Show HN: Turing Pi 2 – a compact ARM cluster with 32 GB RAM

#16

Post by jackyinger »

rektide wrote: post #8

PCIe switching would have been really interesting to see, even in a non-concurrent mode. One also desperately wishes that multi-host network adapters had a low-end market. A 1 x 25Gbe connection shared between 6 hosts would be epic. Or if sharing the connection is too much, just a 4 x 2.5Gbe NIC chip would be acceptably interesting & useful to have. I forget, maybe the gbe is free on the Pi4's chip & this is more of…

PCIe switching sounds nice, but let me tell you that it is a terrible nightmare on every level.

Hardware: these PCIe switches are finicky as all get out; will it link up to your device reliably? Who knows, depends on how the switch and device manufacturers interpreted the PCIe specs.

Software: there is no nice easy standard for connecting host-to-host (which I’m assuming is what one would want on a multinode system Like the one linked). There exists the idea of a PCIe non-transparent bridge, which if I recall correctly, allows CPUs on either side of it to do blind memory reads and writes to each other (hope your IOMMU is set up correctly to protect you from ugliness that could occur here).

Long story short there’s a reason PCIe is a local bus; it was never designed to do anything else. Anything else is largely a proprietary bolt on.

Re: Show HN: Turing Pi 2 – a compact ARM cluster with 32 GB RAM

#18

Post by nsky-world »

billsmithaustin wrote: post #15

I don’t understand the claim about 32GB RAM. The diagram shows slots for four RPi compute modules, each of which has 1GB RAM.

The new compute modules comes with up to 8 Gb of RAM. Here is a detailed review of new CMs https://www.jeffgeerling.com/blog/2020/raspberry-pi-compute-...

Re: Show HN: Turing Pi 2 – a compact ARM cluster with 32 GB RAM

#19

Post by Someone »

billsmithaustin wrote: post #15

I don’t understand the claim about 32GB RAM. The diagram shows slots for four RPi compute modules, each of which has 1GB RAM.

Reading https://turingpi.com/turing-pi-2-announcement/, they have designed a “Raspberry Pi 4 Compute Module (CM4)” with 8GB RAM.

https://www.raspberrypi.org/products/compute-module-4/?varia... also lists it as for sale.

Re: Show HN: Turing Pi 2 – a compact ARM cluster with 32 GB RAM

#20

Post by nsky-world »

jackyinger wrote: post #16
rektide wrote: post #8

PCIe switching would have been really interesting to see, even in a non-concurrent mode. One also desperately wishes that multi-host network adapters had a low-end market. A 1 x 25Gbe connection shared between 6 hosts would be epic. Or if sharing the connection is too much, just a 4 x 2.5Gbe NIC chip would be acceptably interesting & useful to have. I forget, maybe the gbe is free on the Pi4's chip & this is more of…

PCIe switching sounds nice, but let me tell you that it is a terrible nightmare on every level. Hardware: these PCIe switches are finicky as all get out; will it link up to your device reliably? Who knows, depends on how the switch and device manufacturers interpreted the PCIe specs. Software: there is no nice easy standard for connecting host-to-host (which I’m assuming is what one would want on a multinode system L…

Totally agree
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