7 ms·
Naive questions: - Will Huawei be able to use this processor design (now that it is open sourced) to build it's own chips, bypassing ARM restriction & US IP ?
by olivierduval 7y ago
Naive questions:
- Will Huawei be able to use this processor design (now that it is open sourced) to build it's own chips, bypassing ARM restriction & US IP ?
- Are these processor designs usable in mobile device, or only in workstations and servers (using to much power for example) ?
- somepig 7y agoPOWER is about as far from a good fit for most ARM applications as you can possibly get. It's all about shoving a ton of hot power hungry multithread cores as close together as you can and running them at full bore.
- amock 7y agoPOWER already has a place next to arm https://en.wikipedia.org/wiki/QorIQ https://en.wikipedia.org/wiki/QorIQ.
- somepig 7y agoPOWER and Power (formerly PowerPC) are similar but quite different. PPC has been in embedded (but generally not mobile) for quite a long time, but even then, the cores are still hot, power hungry, and poorly suited for mobile.
- StillBored 7y agoBecause the designs predate the big push into extremely high efficiency processors. Like the big "server class" processors, the investment required to create a truly high efficiency processor is quite large. Small in-order cores with limited functional units, and lacking much of what makes a modern processor fast (vector units, specialty instructions/etc) can fool people into thinking that minimal clock domains/gating is sufficient to create a high efficiency design.
- monocasa 7y agoThe Freescale/NXP 4xx/75x PowerPC cores are fairly common embedded CPUs. These days POWER and PowerPC are the same ISA.
- somepig 7y agoNo. POWER and PPC are decidedly not the same. the closest they ever came together was the G5's 970. 4xx and 75x were OK for embedded a decade ago, but today they're hot and power hungry. You can use them in devices where you can burn 10+ watts to maintain backwards compact with existing PPC code, but they're way the fuck too hot for a phone.
- monocasa 7y agoOn the same process node, PPC chips aren't anymore hot than ARM.
- classichasclass 7y agoThat's true for 32-bit, but 64-bit PowerPC is pretty much synonymous with Power ISA.
- deleted 7y ago[deleted]
- shawnz 7y agoBut is that due to ISA differences or just microarchitectural differences?
- temac 7y agoThe ISA is mostly the same. I mean, look at https://www.ibm.com/support/knowledgecenter/en/ssw_aix_72/assembler/idalangref_mig_source_prog.html https://www.ibm.com/support/knowledgecenter/en/ssw_aix_72/as... There are differences in details about uncommon instructions, irrelevant assembly language changes, some instructions privileged for one arch and not the other, that kind of things. But for the bulk of the ISA, it's the same. You probably can create a single userspace binary compatible with both? Not sure but seems doable. The microarch is likely different but then it is also different between several members of each category, so the word does not really designates the micro-arch, but really the ISA. And then you have other brand names using that, and they are so similar that e.g. Freescale switched from PowerPC to Power while incrementing PowerQUICC II to III. I remember Linux has an eieio macro that just emits the aforesaid instruction for PPC, and actually the opcode does something similar on Power (mbar) and IIRC the assembler is happy to emit it regardless of the ISA. So it was kind of messy when you reached the differences, but everything was quickly workable and you got use to it. The reference manuals of Freescale are very good and the "[...]Programmer’s Reference Manual for Freescale Power Architecture Processors" EREF_RM often directly points at the few differences with PowerPC.
- blattimwind 7y agoIBM targets the scale-up market (few big, fast machines) with POWER instead of scale-out (many small, slower machines). Consequentally they are high performance but not particularly tuned for high efficiency, because performance is the more important design goal of the system.
- dragontamer 7y agohttps://en.wikipedia.org/wiki/PowerPC_e6500 https://en.wikipedia.org/wiki/PowerPC_e6500 Freescale hasn't made a new low-power Power chip in a while, but... historically speaking, there were a lot of low-wattage / efficiency-focused embedded POWER designs. I don't know what happened politically between the companies to use ARM instead. But I would imagine that ARM's instruction set was cheaper (or maybe easier) to engineer than Power ISA. Hopefully Freescale engineers can chime in on the discussion, because I'm really just shooting from the hip here. I would expect most issues to come down to business politics. IBM open sourcing the PowerISA is also a business politics move (I guess they hope to recapture the lost ground in the embedded space). PowerISA means operating with IBM's ecosystem: GCC, Linux, etc. etc. Remember IBM has merged with RedHat, so there's a lot of promise for Linux support that ARM and RISC-V don't necessarily provide. I think this is a good move.
- floatboth 7y ago> promise for Linux support that ARM and RISC-V don't necessarily provide uh, ARMv8 and RISC-V were developed with Linux in mind from the beginning, they didn't even have anything other than Linux/BSD/various-RTOSes, like IBM did with AIX.
- dragontamer 7y agoThat's not the kind of support I'm talking about. Who is writing the RISC-V compiler? If the RISC-V compiler for GCC or CLang messes up, who do you call? If the Power9 GCC / CLang compilers mess up, you call Red Hat for support. Red Hat / IBM are now the same company, so they'll offer end-to-end services. ----------- ARM has okay support: the ARM foundation seems to be taking care of their compiler kits / Linux patches / etc. etc. pretty well. But I don't think you can buy an ARM support package from anybody... really. I think the ARM / Linux ecosystem is still nascent. You get good support through the Rasp. Pi community, and maybe the occasional Android Phone gets a big community around it. But ARM / Linux ecosystem is quite poor outside of Rasp. Pi. ARM, as a company, is clearly designed as an "embedded" company. It provides the documentation and compilers, but doesn't provide too many OS-level services above that.
- xvilka 7y agoRISC-V is a better fit for mobile devices. But Huawei does produce network hardware that might benefit from a good POWER-based platform.
- Symmetry 7y agoWhat aspects of RISC-V do you think make it a better fit?
- als0 7y agoI'd also like to know, but I imagine that the compressed version of the RISC-V ISA would be a significant factor as code density is important for a phone.
- Iwan-Zotow 7y agoreally? for last three-four years phones have ca 2-3-4Gb of RAM and 32-64Gb of storage nad if are talking about RISC-V phone, it would be produced in no early than 2020, so not sure code density is a significant factor I don't think
- monocasa 7y agoCode density matters for I$ thrashing reasons, but it's probably not a significant enough factor to overtake the market supremacy of ARM.
- f00zz 7y agoAbout the first question, UltraSPARC has been open source for a while. You can even download the Verilog code. We haven't seen any UltraSPARC-based processors, so I don't see why they would use this.
- pkaye 7y ago> Will Huawei be able to use this processor design (now that it is open sourced) to build it's own chips, bypassing ARM restriction & US IP ? Which operating system would the use? Is that supported with the power instruction set?
- cmrdporcupine 7y agoPower is totally mainstream and well established. You have your choice of a bunch of operating systems and compilers. Linux, llvm/clang, GCC, etc. all there for a really long time. Windows also ran on the PowerPC architecture at various points. In 1996 I worked briefly a company that had a bunch of "PERP" ("PowerPC Reference Platform") machines lying around given to them by IBM that for application porting to Windows NT PowerPC. For kicks, I put Linux on them, so they'd actually be useful for something. PowerPC is not strictly identical to Power architecture, but is related and most tools and OSes can be made to work either.
- Symmetry 7y agoWhat's being released here is the instruction set architecture, not the microarchitecture for any particular processor design. As RISC ISAs go Power is relatively pragmatic, though not to the extent 32 bit ARM is, so it has relatively good code density compared to SPARC and MIPS. Plus it doesn't have annoying misfeatures like branch delay slots or register windows. For mobile processors it seems about as good as 64 bit ARM but with a bit less software support in the mobile world, though a good history of software support in general.
- tpearson-raptor 7y agoAn interesting offset for the latter is that you could develop your software on a high end system that matches the mobile architecture. Anyone who has has to fight with (/slow/) pure emulation of e.g. Android on ARM knows the pain this causes, multiplied by the thousands of developers. That's a lot of wasted man hours vs. the develop on same architecture model.