Server and endpoint, or dual cpu server?

[Miska]

8 hours ago, seeteeyou said:

There's also NUMA once we've got a pair of processors

 

You have NUMA also with number of modern single-socket CPUs such as many latest AMD processors that have two "chiplets" in the same package. So you may have a multi-layer NUMA for example with AMD EPYC CPUs.

 

On 11/5/2019 at 11:07 AM, Gavin1977 said:

My next thought is how a dual CPU server would compare with a virtualised system on a multicore processor

 

Both carry some extra overhead, especially virtual machines, but dual-socket has double the memory bandwidth compared to single socket. Virtual machines of course only add extra overhead, but don't create any additional benefit in terms of performance.

 

On 11/1/2019 at 11:46 PM, Gavin1977 said:

I thought it would be useful to start a new thread for this.  What provides the best audiable benefit... server and endpoint, or a dual cpu server?

 

Not related at all. Dual-socket (or quad-socket or what ever you like) just adds more CPUs and memory bandwidth to the computer. With some overhead also baked in due to NUMA.

 

Advantage of a separate networked endpoint is to allow locating big loud servers outside of listening spaces. And also use of very low power system with minimal activity as endpoint.

 

2 hours ago, Gavin1977 said:

dual CPU motherboard such as this one might well have the potential to be 'better' than a single CPU solution as all of the heavy lifting is done by one of the CPU's leaving one CPU as an endpoint as Seeteeyou suggests

 

Can you explain why it would be any better? The other CPU in this kind of case would be still a big beast anyway.

 

8 hours ago, seeteeyou said:

On the software side, things could get quite interesting when the size of the entire Windows folder alone is getting all the way down to less than 60MB

 

On software side, things get interesting when you get rid of Windows and go for a custom Linux where you have all the source code available and can modify all the aspects of the operating system....

 

[Miska]

On 11/8/2019 at 12:53 PM, Gavin1977 said:

Shame Epyc processors have such high TDP, I have looked at AMDs new Embedded V1605B - but it's just a single die.  So no opportunity for Numa / dual CPU style optimisations there.  An Epyc system would be reliant on a HDPlex or Paul Hynes SR7 to satisfy these levels of power consumption - I'd like to keep within a lower power budget.

 

There's not much point in making NUMA system with small CPUs, because the overhead would be still there but you wouldn't get benefits. When you have enough processors to starve single socket memory channels, you need to add more memory channels by using NUMA. Another, more efficient alternative is to do like GPUs do, where they just scale the memory bus width to 512 bits and up. So you don't get overhead cost of NUMA, but you get NUMA worth of memory bandwidth.

 

Biggest GPUs use 4096-bit wide memory bus with HBM2 memory.

 

So instead of using two sockets, I've been opting to use CPU + GPU. Which is another kind of NUMA architecture, both having their own RAM but the interconnect between the two mapped memory regions is 16x PCIe. Plus depending on case, a separate network endpoint.

 

[Miska]

52 minutes ago, Gavin1977 said:

You've opened up another can of worms 🙂 Shame GPU cannot be used as a USB endpoint as well (HDMI I2S perhaps though).

 

There wouldn't be any point in using GPU as USB endpoint. I2S shouldn't be used to connect devices at all, it is only for chip-to-chip interconnect.

 

53 minutes ago, Gavin1977 said:

You've got me thinking about PICMG 1.3 / SHB Express combinations to interconnect two computers.  Anyone have experience with this?

 

I fail to see point of that, it would be same as having two computers on the same motherboard.

 

I much rather use Ethernet.

 

56 minutes ago, Gavin1977 said:

I tried to set up a linux virtual PC (using Hyper-V and also Virtual box) and tried to get it to boot from my copy of Euphony on USB (because Euphony needs a dedicated hard drive), but no luck getting this configuration to work at the moment the virtual pc won't boot.

 

Using virtual machine for audio is extremely bad idea because of the overheads you just have massively increased latencies, etc.

 

If you want two machines, you are much better off with two real machines.