On 9/17/2019 11:58, David Brown wrote:
> On 17/09/2019 06:26, Rick C wrote:
>> On Tuesday, September 17, 2019 at 12:11:05 AM UTC-4, Dimiter wrote:
>>> On 9/17/2019 5:11, Rick C wrote:
>>>> On Monday, September 16, 2019 at 4:24:40 PM UTC-4, Dimiter
>>>>> On 9/16/2019 21:36, kristoff wrote:
>>>>>> HI all,
>>>>>> I know is this kind-of old news by now, but -as far as I see-
>>>>>> this has not been discussed here:
>>>>>> IBM is open-sourcing their PowerPC processor design.
>>>>>> (E.g. see here and other links:)
>>>>>> As PowerPC processors do are used in embedded devices, anybody any
>>>>>> what this would mean for the embedded-processor market? Are
>>>>>> we now going to be flooded by Chinese ppc-based devboards?
>>>>>> And is this going to kill the risc-v?
>>>>> If someone takes on and starts making more power architecture
>>>>> processors the impact could be huge, this is by far the best
>>>>> architecture I have seen in my life - and I have explored most
>>>>> of them (and used power for decades now). Then it might make no
>>>>> impact at all, how many of those making decisions of such
>>>>> magnitude can see further than the next quarter report and can
>>>>> look into something other than what "everybody is doing".
>>>>>> BTW. Does anybody have an easy-to-use overview of different
>>>>>> powerPC architectures out there? (especially for embedded
>>>>>> I've been trying to understand the different wikipedia pages
>>>>>> on the powerPC architectures, but it all seams to one giant
>>>>>> mix of names, numbers and 'books' from a dozen different
>>>>> The only maker of Power architecture processors is NXP (since
>>>>> they acquired Freescale). IBM had an embedded core some ages
>>>>> ago, 401 or something like that, which some other company -
>>>>> AMCC I think - took on but I never used any of these.
> There are others that have made PPC based devices in the past. But I
> think NXP is the only company making microcontrollers and network
> processors based on PPC in any serious way. ST has (last time I looked,
> which was a while ago) second-source copies of a number of NXP PPC
> microcontrollers, but I don't think they had any of their own.
>>>>>> Cheerio! Kr. Bonne,
>>>>> Thanks for posting, I had missed the news so this is new to
>>>>> me. Good news I suppose, gives some hope that this great
>>>>> architecture will survive after all.
>>>>> Hopefully I can migrate DPS to 64 bit power sooner rather than
>>>>> later, I have been wanting to do it for quite some time now.
>>>>> Might also be some help.
>>>> Maybe I'm not remembering it right, but I thought the PPC fell
>>>> out of favor because as processors got faster and more complex,
>>>> the PPC architecture lost it's advantages. I would seem I am not
>>>> remembering this correctly.
>>> The architecture did not lose its advantages, it is just as silicon
>>> got faster messy designs like the x86 could run fast enough for the
>>> general population.
> The key change, I think, was the move from x86 cores that ran x86 code,
> to x86 processors that translated x86 instructions into an internal RISC
> code that is executed on a RISC core. RISC designs and load-store
> architectures with lots of registers are much better suited to fast
> execution, pipelining, OoO execution, and super-scaling than CISC ISAs.
> Once x86 cpus started using RISC cores internally, much of the
> advantage of PPC is lost in comparison.
> And x86 has several advantages that PPC can't get, beyond the obvious
> compatibility with x86 binaries. One is the x86 strong memory model -
> it is a good deal simpler for programmers than weaker memory model of
> most RISC designs, and a lot of code is written with the assumption of a
> strong memory model. The PPC exposes the guts of its RISC core to the
> programmer - and thus cannot easily change it - with x86 cpus, their
> RISC cores are hidden and designers can change it as they want for each
> new chip. They can have 37-bit wide instructions, completely re-arrange
> the encoding, add hundreds of registers, etc., whereas PPC designers
> have to stick to the ISA.
> Of course, PPC implementers could move in this direction too - turning
> PPC RISC instructions into an expanded internal RISC design for
> execution. I think the size of the ISA might make that harder than for
> the x86, and it won't solve the memory model challenge, but it could
> work. But they haven't had the same motivation - they haven't hit the
> same performance brick wall as the x86 world faced.
Well emulating a processor on another - like Intel do - is nothing
particularly new, I myself have emulated the 6809 on power under dps
(had some code written in the mid 80-s which I still can - and do -
However no matter how efficient your emulation is it is an emulation
and has its performance cost. Under equal circumstances power can
beat Intel hands down. No such comparison can be made though,
if you compare this or that piece of C software you will compare
a compiler to another rather than a core to another - so Intel
will likely win simply because of its huge popularity, the man
hours put into compilers for x86 must outdwarf these put into
So a performance comparison just cannot be done in a decent way.
>>> I don't know how far did IBM go developing it, may be they still
>>> do. I know only the Motorola/Freescale line, some of which I have
>>> used and am using. Their latest designs are 64 bits QORIQ (someone
>>> got away without being punished for that name) which look quite
>>> good really.
>> There has to be some reason why they lost the war other than
> No, there doesn't. IBM have demonstrated in the past that they are
> capable of technical excellence combined with extraordinary screw-ups by
> sales, marketing, purchasing and licensing departments that don't
> understand the products, and don't talk to each other. The whole sad
> OS/2 story is an example.
> That doesn't mean there /aren't/ other reasons, merely that
> non-technical reasons can be enough.
>> Apple was using the PPC and many others. So there was
>> clearly a market. Perhaps I didn't state things correctly. The
>> advantages of the PPC must not have been significant enough in larger
>> chips to make continued development of ever more expensive designs
>> worthwhile. I recall when IBM dropped out of the race. They must
>> have seen the handwriting on the wall.
> Certainly keeping in the race was getting more and more expensive.
> Intel could use their server chip money to pay for it, but IBM did not
> have high-margin PPC customers (there Power cpu > line for big iron is
> separate) screaming for faster cores.
At the point where Apple abandoned PPC and went Intel what I remember
was Jobs saying Freescale (or wast it still Motorola SPS) or IBM or
both could not deliver the silicon they wanted, i.e. it was a production
complaint. I am not sure I buy into that, I have my conspiracy theory
about what happened but well, it is just a theory of mine, I can't
prove it and it might well be wrong on top of that.
>> So how does Freescale keep paying for spins on 64 bit chips? I take
>> it they still can hold a match to the Intel processors, rather they
>> are now competing with the ARMs of the world?
> They don't. No PowerPC devices come close to top Intel/AMD processors.
> And for the devices NXP make, the core speed is not critical. NXP make
> two types of PPC devices - automotive / high-reliability devices (up to
> about 300 MHz core speed), and networking (up to 1.5 GHz core). For the
> automotive devices, reliability, robustness and peripherals are key, not
> the core or the core speed. For the networking devices, it is the
> networking hardware that is key - the core is for control, not for
> processing. AFAIK all NXP's PPC chips are 32-bit.
Oh no, they have 64 bits for years now. Just check the website, they
have up to 8 physical cores and 16 logical ones (or was it 4/8),
just look for QORIQ power. Really powerful beasts they are, GHz
range, 750 MHz clocked DDR4 etc., that on a SoC.
> There is often a confusion between "Power" and "PowerPC". It doesn't
> help that NXP talks about their "Power" devices when they mean "PowerPC" >
> The "Power" architecture is IBM's big iron chip, and these are big,
> fast, expensive, power-hungry, and full of big iron features like
> redundancy, hot-plugging (for memory, cores, etc.). They are made by
> IBM, and they run the many of the top supercomputers as well as every
> bank in the world.
> "PowerPC" was an initiative started by IBM, Apple and Motorola - taking
> the basic ISA from the Power world, removing all the "big" features, and
> making something that could be implemented in a single chip that was
> competitive in size, speed and cost with the x86's and 68k devices of
> the time, but with a scalable future.
PowerPC (PPC) was dropped some 10 years ago as a name, it is called
"Power Architecure" nowadays. Not to be confused with IBM's Power
from the 80s, which is sort of the same but not quite, this is where
the architecture originated (the guy who did it has been really good).
Of course people use PPC and power interchangeably nowadays so unless
you are intimate with what is on offer it can be a source of confusion.
Dimiter Popoff, TGI http://www.tgi-sci.com