Bunch of Xeon Phi's vs Threadripper

[rsethc]

I don't know any in-depth details about how Xeon Phi's work but my basic understanding is that they behave like normal CPUs that you can add via PCIe add-in cards. Today I wondered about two things:

1. If you bought a mining motherboard (you know, one of those that has like 20 PCIe slots), and enough Xeon Phi cards to completely populate it, would it work at all?
2. And if it did work, and you ran some synthetic CPU benchmarks and productivity workloads on it (I would expect gaming to completely suck), how would it compare to just a single 64-core Threadripper?

Or if anyone wants to chip in w/ an explanation of just how those cards worked in general, that would be pretty cool to know as well.

[Guest]

It's like thinking 20,000 kids can do more work building a skyscraper than 100 trained adults.

 

I am horrifically oversimplifying, but yeah... purpose built and all that.

 

 

[rsethc]

What I'm wondering about in terms of the "how do they work" part is more like: how do they access memory (do they have onboard memory too?), and how does the OS become aware of those cores? If everything has to go over PCIe routing, is it only certain motherboards that support them (like you'd have to have a certain chipset, such that those mining boards won't work)? Or is it something the OS has to have had support implemented for, or is it a driver...?

[thedangerine]

I feel like they would be trash compared to the threadripper because they really aren't designed for that kind of use at all, Xeon phi isn't really the same as slap a bunch of cpu's on via pci express and fire up cinebench to get the best score ever, they are reallly meant to be used in servers for scientific research and stuff like that

[GDRRiley]

xeon phi only work with some motherboards if they are PCIE, if they are socket based you only get one.

threaderipper and epyc destroy Phi 

[GDRRiley]

https://docs.nersc.gov/systems/cori/knl_modes/

 

[Electronics Wizardy]

15 minutes ago, rsethc said:

What I'm wondering about in terms of the "how do they work" part is more like: how do they access memory (do they have onboard memory too?), and how does the OS become aware of those cores? If everything has to go over PCIe routing, is it only certain motherboards that support them (like you'd have to have a certain chipset, such that those mining boards won't work)? Or is it something the OS has to have had support implemented for, or is it a driver...?

all the pcie ones have their own memory on board.

 

You don't just get more cores on the host system, you need to make software that will run on that node explecity. The pcie cards run linux them selves, and you need to put the jobs on the cards.