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mobile computers replacing desktopmobile computers replacing desktopPosted Sep 10, 2012 1:51 UTC (Mon) by Cyberax (✭ supporter ✭, #52523)In reply to: mobile computers replacing desktop by dlang Parent article: Improving Ubuntu's application upload process
Because IBM sells stuff to entities that think along the line: "the more expensive the better" and "we're not going to use all these new-fangled x86 CPUs, if PowerPC was good enough for Abraham Lincoln it's good enough for everyone!"
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mobile computers replacing desktop Posted Sep 10, 2012 2:23 UTC (Mon) by dlang (✭ supporter ✭, #313) [Link]
There are lots of situations where the Power chips are far better than the x86 chips.
The question is if this added capabilities are worth the money.
If you have an application that is easy to split across multiple systems, the answer is probably no, but for applications that are harder to scale, the dramatic improvement in per-thread performance on a Power chip can be worth a LOT.
x86 didn't win because it was better than it's competition, it won because it was more common. It was more common because it was 'good enough' and cheaper than the competition, and it is what happened to be picked for the PC that got cloned.
In many ways x86 is a far worse architecture than just about anything out there. But AMD and Intel have put HUGE amounts of effort into speeding it up. But even with all this effort, it's not the best performing chip available, and it's not the most power efficient chip available
mobile computers replacing desktop Posted Sep 10, 2012 2:35 UTC (Mon) by Cyberax (✭ supporter ✭, #52523) [Link]
Not really. It's just that IBM is willing to produce CPUs that cost $20000 each (I'm not exaggerating) by brute force (using large dies). That's why they can get to 6GHz clock speed.
That could be easily replicated by x86 using the same methods. But Intel and AMD probably are not interested. It's a niche, after all.
mobile computers replacing desktop Posted Sep 10, 2012 2:48 UTC (Mon) by dlang (✭ supporter ✭, #313) [Link]
I'm not disputing that it's a niche.
However, the x86 architecture is rather poor in many areas (extremely low register count for example)
Sparc, Power, Alpha are all better architectures than x86 (or amd64), but since they can't run the software that can run on x86, and that software is a huge percentage of the industry, they are limited to the server niche.
the highest performing processors always have a large price premium attached to them. IBM makes really good profit margins on the Power line, but they do also include capabilities that are not found on x86 systems. These capabilities are usually not worth their cost, which is why it remains a niche, but if you need them, they are cheap at that price.
But the point was that just because they didn't jump on the latest bandwagon doesn't mean that they went bankrupt.
mobile computers replacing desktop Posted Sep 10, 2012 3:08 UTC (Mon) by Cyberax (✭ supporter ✭, #52523) [Link]
Let me quote the inimitable Linus Torvalds: http://yarchive.net/comp/linux/x86.html
>And the baroque instruction encoding on the x86 is actually a _good_
>The low register count isn't an issue when you code in any high-level
And that's true. ARM folks found out that while ARM is nice and great for low-performance low-power computing, you really need to do all sorts of tricks x86 does once you want to move to high-performance computing. Large register file does not give you much in that case.
mobile computers replacing desktop Posted Sep 10, 2012 5:44 UTC (Mon) by dlang (✭ supporter ✭, #313) [Link]
on the other hand, the x86 design is hard to scale up in speed and efficiently use more transisters. Other designs do scale up better.
mobile computers replacing desktop Posted Sep 10, 2012 6:33 UTC (Mon) by khim (subscriber, #9252) [Link] Not really. There are designs which can cover lower-power/lower-speed niche (ARM and MIPS), there are designs which cover higher-power/higher-speed niche (Itanic, POWER), there are no designs which scale better than x86. That's why most TOP500 computers use it: they need something with the best available performance per watt (wall-power is one of the most important limitations for the supercomputers) and that "something" is either GPU or x86. Often both.
mobile computers replacing desktop Posted Sep 10, 2012 6:56 UTC (Mon) by Cyberax (✭ supporter ✭, #52523) [Link]
Technically, the latest ARMs have a better peformance/power ratio than x86/64. But they still can't approach the single-core speed of x86.
mobile computers replacing desktop Posted Sep 10, 2012 7:07 UTC (Mon) by dlang (✭ supporter ✭, #313) [Link]
> Technically, the latest ARMs have a better peformance/power ratio than x86/64. But they still can't approach the single-core speed of x86.
which doesn't approach the single-core speed of the Power systems.
each of them has a market, they don't have to directly compete.
Unless you are shipping binary-only software and aren't willing to ship multiple copies. the industry has been in that mindset for a long time.
But in the mobile space they don't have the luxury of having a single binary target, and until and unless they do (which seems unlikely to happen in the short term), we have a real chance for competition between different processors, and for different processors to be used in different places. In the short term it's easier to try and mandate a hardware monoculture, but I don't think anyone has enough power to do so, especially with Android and Linux _not_ mandating it and giving everyone an example and an option to work with when they run into the monoculture limitations.
mobile computers replacing desktop Posted Sep 10, 2012 11:55 UTC (Mon) by Cyberax (✭ supporter ✭, #52523) [Link]
> which doesn't approach the single-core speed of the Power systems.
It does. Easily.
New Xeons beat all the PPCs except for the top-of-the line POWER-7 CPUs. And then top-of-the line PPCs beat Xeons only because of their humongous die size and clock speeds (with corresponding TDP).
In reality there's no magic sauce that makes PPC to be inherently better than x86. They both use hardware decoders to split instructions into pipeline-able sub-instructions. Sure, decoders for RISCs are easier to implement but the difference in the number of transistors is trivial for desktop/server CPUs.
I'd several run-ins with IBM mainframe guys about a year ago. They told my client how great and fast their mainframes were, that $100000 per system couldn't be wrong, could it? So my client went and leased a 'small' unit - telling how great it would be.
IO turned out to be slow as hell compared to our simple Xeon-based server with a RAID of Intel SSDs. CPU performance indeed was higher, but not by much - and we got one of the fastest CPUs available.
mobile computers replacing desktop Posted Sep 10, 2012 13:16 UTC (Mon) by khim (subscriber, #9252) [Link] But in the mobile space they don't have the luxury of having a single binary target, and until and unless they do (which seems unlikely to happen in the short term), we have a real chance for competition between different processors, and for different processors to be used in different places. Define "short term". We had similar situation on PC, too. Early versions of many programs supported many different CPUs (I've personally used Turbo Pascal on x86-based systems and on z80-based systems). But eventually market settled on "IBM PC compatible" and most other systems died of. Mac survived (barely), but all other IBM PC-incompatible personal computers perished. x86-incompatible systems perished without exceptions. This is why Intel and MIPS are so desperate to push their CPUs in mobile space: they know that if they'll not do that in a year or two they'll lose the opportunity forever. Already the biggest complaint WRT x86-phones Androids and MIPS-based Androids is poor ARM emulation and poor work of many popular programs with binary-only components. In the short term it's easier to try and mandate a hardware monoculture, but I don't think anyone has enough power to do so, especially with Android and Linux _not_ mandating it and giving everyone an example and an option to work with when they run into the monoculture limitations. Bwa-ha-ha. Just want and see. Windows NT also supported multitude of CPUs (), but in the end… market have chosen just one architecture: x86. Short-term? Nope, this is not the question of short-term. I'm not sure who'll win the mobile race (there are still some time left and MIPS and x86 both have advantages: MIPS is free and x86 makes it easy to port software from PC), but in the end it'll be one choice.
mobile computers replacing desktop Posted Sep 10, 2012 6:02 UTC (Mon) by khim (subscriber, #9252) [Link] But the point was that just because they didn't jump on the latest bandwagon doesn't mean that they went bankrupt. Oh yes, it does. IBM sold out it's PC division because it was unprofitable and they no longer sell workstations, too. They survived by shifting to other venues, they are doing consulting work, they are selling mainframes, they no longer produce PCs or workstations. That part is gone. The problem with most players in desktop area today is that they have no plan B, or if they do (HP has printers and enterprise software, for example) they are not big enough to support the whole structure. Today they have difficult dilemma: either they will try to shift to mobile or they need to switch to some other field (like IBM did 20 years ago). Desktop will no longer support them. They have time (you right: right now, today mobile apps tend to be very weak at doing any content creation), but it's large shift, I'm not sure they have enough time.
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