[calibwam]

I don't like predicting the future.

> So give up on parallelism already. It's not going to happen.

> End users are fine with roughly on the order of four cores,

> and you can't fit any more anyway without using too much

> energy to be practical in that space.

End users was fine with a single core Pentium 4 on their workstation. We progressed. How would even Linus know that we won't find a way to make parallel work en masse?

[bad_user]

First of all I think that many people are still fine with single core Pentium 4 workstations and that what we have today is not that much better. For example the "death of the PC" was greatly exaggerated by the simple fact that people aren't upgrading so often because their 4-6 year old workstations are still good enough for most purposes.

Of course, many of us do need the extra power. But what Linus is saying and I agree with him, is that for mobile devices (phones, tablets, laptops), Moore's law doesn't work so well, as batteries aren't keeping up with Moore's law. A mobile device that doesn't last for 2 hours of screen-on usage is a completely useless mobile device (and here I'm including laptops as well).

[dagw]

End users was fine with a single core Pentium 4 on their workstation.

Not really. 2-4 cores have been available on workstations for decades, so no one is arguing the 1 core is all you need. Even Linus is saying that having 4 cores is probably a good thing in many cases. The argument is not 1 vs 4, but more 4 vs 64, especially if you assume a fixed power budget.

[calibwam]

I'm not saying they would be fine now, but once (10 years ago), that was what you had. And now we have 4-8 cores on our laptops, and 2-4 on our phones. Why shouldn't we have 64 cores in the future if we solve the programming problems, and can make them energy efficient? Just because 4 cores are fine now, doesn't mean we shouldn't try to increase that.

[dagw]

but once (10 years ago), that was what you had.

No it wasn't. Multi-processor Intel based workstation have been available since the very early 90s. People have realized for a very long time that having 2-4 cores is useful.

I'm still not convinced that, given that I have X Watts to spend, that I'm not better off with 4 CPUs using X/4 Watts each rather than 64 cores using X/64 Watts each. But I'm willing to be proven wrong.

[calibwam]

Really? Do you mean people chained together multiple processors, or that Intel produced something? For I can't find it and would be interested in reading about those old systems.

[fulafel]

Intel was relatively late to the game, their multiprocessor support started getting decent around the Pentium Pro. The Unix workstation vendors (Sun etc) had dual CPU workstations a while earlier, but mostly SMP was used in servers.

https://en.wikipedia.org/wiki/SPARCstation_10

Feather in the hat for first multi-core CPU on single die goes to IBM and the Power4 in 2001, preceding Intel's attempt by ~4 years. (Trivia: IBM also sold a Power4 MCM with 4 Power4 chips in a single package).

(Yes some people managed to stitch together earlier x86 processors too with custom hardware, but it wasn't pretty or cheap or fast).

[tbyehl]

Sequent had proprietary multi-processor 386 systems. The Intel MultiProcessor Specification dates back to 1993. Most Pentium II chipsets supported dual processors, which drove pricing down enough for enthusiasts to build them for home use.

[dagw]

There where a handful of companies making 2-8 socket motherboards for 486 processors. I know Compaq and NCR were early in offering workstation based around those motherboard designs.