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IBM Unveils Next Generation Dual-Architecture Processor for IBM Z and LinuxONE

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Re: IBM Unveils Next Generation Dual-Architecture Processor for IBM Z and LinuxONE

#31

Post by bryanlarsen »

christkv wrote: post #26
bryanlarsen wrote: post #19

Earlier quoted context omitted.

No, this is more like any modern processor, which translates instruction codes into micro-ops. To over-simplify IBM just has two of these units per thread rather than one.

I wonder how they handle potential differences in memory barriers, instruction order scheduling and other stuff and do they run the core in one mode continuously or do the mix instruction streams from different instruction sets? Anybody got a link to an article?

I had much the same question, which is one of the reasons I used the term "over-simplify". my guess is that many of the units have a toggle "arm mode / z mode", which would mean that mixing streams would be unlikely. I wonder if they chose ARM over x86 or other options partly because important aspects like the memory model of ARM and z were more similar than the memory models of x86 and z.

Re: IBM Unveils Next Generation Dual-Architecture Processor for IBM Z and LinuxONE

#32

Post by tempest_ »

wmf wrote: post #21
crmd wrote: post #2

I was reading HN comments yesterday shitting on modern IBM for being a non tech consulting company that has not innovated since the mid nineties.

The z mainframe team does good technical work but then the high price cancels out all the value of that work. I'm not sure if that counts as innovation or not.

At this point no one is buying into mainframes are they?

So they are just selling to the existing pool of users for which the price just has to come in under the cost/risk of rewriting all their ancient stuff.

Re: IBM Unveils Next Generation Dual-Architecture Processor for IBM Z and LinuxONE

#33

Post by to11mtm »

pavlov wrote: post #7
crmd wrote: post #2

I was reading HN comments yesterday shitting on modern IBM for being a non tech consulting company that has not innovated since the mid nineties.

More like mid-2000s, even with the least charitable interpretation. There was a time when IBM dominated console CPUs for a massively successful generation (PS3, Xbox 360, Nintendo Wii).

It's a little more complex than that, IMO.

For starters, IBM did also do the CPU for the GameCube, and that was likely a part of the Wii using an upgraded PPC arch for that.

On the flipside, there is the theory (I think even Copetti brings it up in their XBox 360 Architecture breakdown [0]) that IBM using the Cell PPE for the 360's tri-cores left a sour taste in Toshiba, but more-so Sony's mouths.

I think the big 'X factor' though, was that, for as much pain as it caused AMD in the short term, (it's so easy to forget their 'malaise' era, i.e. Early Bulldozer and the GloFo split pains to their margins[1]), AMD made all the 'right' choices to let the console vendors have their cake and eat it too.

Namely, AMD was more than happy to do a custom core if there was a volume contract (similar to what IBM was willing to for the 360/GC/Wii) but also now had a capable, in-house GPU. (And thankfully had Bobcat as a stepping point towards Jaguar[2])

There's part of me that asks, if AMD had an ARM core, if we would have all Consoles powered by AMD chips now. Nintendo likely bought into Tegra because it was an ARM core, and for better or worse their mobile stuff by the time of making that choice had 15+ years of proven ARM success (GBA, DS, 3DS) behind it.

(See also, Intel in the 2010s scrambling with half-assed promises of integrating custom functionality or FPGAs with x86 cores.)

[0] - https://www.copetti.org/writings/consoles/xbox-360/

[1] - From what I recollect, the GloFo split and how the contracts were drawn up as far as their production, had a huge impact on their ability to produce due to yields and thermals, as well as the contracts for how GloFo got paid; it was at least part of them diversifying with TSMC as soon as they reasonably could.

[2] - As a Rant, I am pretty sure, if Jaguar had Desktop/Mobile versions that included a Dual channel DDR controller, they would have cleaned up on the low cost laptop market. I had one with, I think it was an A5000 or A5200, and for how tiny the battery was it could last wayyyy longer than any of the intel laptops I had for the time, but churned if you were doing memory heavy stuff.

Re: IBM Unveils Next Generation Dual-Architecture Processor for IBM Z and LinuxONE

#35

Post by to11mtm »

Retric wrote: post #29
rbanffy wrote: post #24

Earlier quoted context omitted.

> Xbox 360 used an Intel CPU. No. It was a PowerPC based one called, IIRC, Xenon.

Wow, you’re right. Xeon vs Xenon I had always assumed with chip names that similar it was an Intel product. How on earth didn’t they get sued?

I'm guessing that they were safe in that it was more or less a 'codename' for a specific product's CPU that nobody else could buy, versus a product out on the market, left enough clear separation to avoid Trademark complaints.

The combined might of IBM and Microsoft's legal teams, even (possibly even moreso?) then, was better than Intel's to be sure.

Re: IBM Unveils Next Generation Dual-Architecture Processor for IBM Z and LinuxONE

#36

Post by rbanffy »

christkv wrote: post #26
bryanlarsen wrote: post #19

Earlier quoted context omitted.

No, this is more like any modern processor, which translates instruction codes into micro-ops. To over-simplify IBM just has two of these units per thread rather than one.

I wonder how they handle potential differences in memory barriers, instruction order scheduling and other stuff and do they run the core in one mode continuously or do the mix instruction streams from different instruction sets? Anybody got a link to an article?

Possible different micro ops for different semantics.

They also don’t mix instructions sets within the same process - the diagram I saw had ARM Linux as a guest under z/VM or KVM. For generations now no OS (not VM, not z/OS) hasn’t seen the bare metal machine, only ran under the PR/SM hypervisor, which is what does the logical partitions now.

In order to properly run OSs for the 360 and 370 generations, s390x also has instructions for setting up CPU flags to more precisely emulate older machines. From an s390x binary you can, IIRC, do a jump to an address telling it that, from the jump forward the ISA is the one of a 360 until it encounters a return, which restores 390 mode.

Re: IBM Unveils Next Generation Dual-Architecture Processor for IBM Z and LinuxONE

#37

Post by theandrewbailey »

tempest_ wrote: post #32
wmf wrote: post #21

Earlier quoted context omitted.

The z mainframe team does good technical work but then the high price cancels out all the value of that work. I'm not sure if that counts as innovation or not.

At this point no one is buying into mainframes are they? So they are just selling to the existing pool of users for which the price just has to come in under the cost/risk of rewriting all their ancient stuff.

Someone has to be buying mainframes. Otherwise, there's no point in continuing to develop them. Shareholders would revolt.

Re: IBM Unveils Next Generation Dual-Architecture Processor for IBM Z and LinuxONE

#38

Post by to11mtm »

stonogo wrote: post #12
christkv wrote: post #4

Is this like the Transmeta processors doing code translation in hardware?

They were pretty clear at Hot Chips that it's native

.... I -so- miss RealWorldTech write-ups, I'd love to see what David Kanter would have to say about this thing...

Re: IBM Unveils Next Generation Dual-Architecture Processor for IBM Z and LinuxONE

#39

Post by eschaton »

Retric wrote: post #29
rbanffy wrote: post #24

Earlier quoted context omitted.

> Xbox 360 used an Intel CPU. No. It was a PowerPC based one called, IIRC, Xenon.

Wow, you’re right. Xeon vs Xenon I had always assumed with chip names that similar it was an Intel product. How on earth didn’t they get sued?

Because simple similarity doesn’t usually result in a lawsuit? Especially if one of the words isn’t a public product name and also happens to be an existing word with no existing specific use in the industry.
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