So, am I right in believing that one of the things that keeps a 60MHz 68060 operating seemingly as fast, if not faster in some cases, than a 2GHz Pentium 4

In no cases is 60MHz 68060 faster or even close to as fast as 2GHz P4, not even seemingly. What you're experiencing as "speed" is just the user interface. If you run Workbench on P4 it's even tons faster than on 060. It's all about software.

or is there more to it than I've been able to pick up so far?

There is more to this. Hyperthreading is just something that allows use of the CPU resources that would otherwise be wasted. 68060 doesn't have anything similar in it. See Wikipedia: Hyperthreading.

No. Amiga developers didn't do the same in software.

You're comparing apples and oranges here.

I was leaping to the conclusion that splitting processes into separate smaller units increased efficiency, and concluding that HT's benefits come from a similar, and admittedly more advanced method of task management.

I'm not trying to imply that an 060 = P4 by any means. The notion just occurred to me while watching Windows refresh the display in chunks after copying some fairly large files. Reading up on hyper-threading gave me the impression that the intent is to eliminate such glaringly obvious deficiencies in Windows' multitasking efforts.

Roj wrote:
I could be wrong about this. My knowledge of hardware is somewhat limited, especially modern stuff, but I just bought a hyper-threading processor for my PC, and after having read about the idea behind hyper-threading, I can't help but think that this innovation for PCs is something that Amigas have done for over 20 years.

Hyper-Threading, as I understand it, is the capability of busting large processes up into smaller pieces for the sake of efficiency so that less of the processor is left idle during task execution. One article I've read on the subject indicates that Intel was reluctant to evolve HT because it became clear that HT meant more to the apparent speed of a processor than did processor speed alone, and Intel was relucant to surrender the meaning behind the GHz rating of their processors. AMD has always argued that processor power meant much less to performance than other issues, one of them being HT technology.

So, am I right in believing that one of the things that keeps a 60MHz 68060 operating seemingly as fast, if not faster in some cases, than a 2GHz Pentium 4, or is there more to it than I've been able to pick up so far?

Wow. You really need to read up on these things.

The Amiga had nothing like Hyperthreading. Not even in software (whatever that means).

When Windows appears to do things in chunks, that has nothing to do with Hyperthreading, either.

Hyper threading does not split a large program into smaller parts. That idea is simply known as threading, which is quite simple to implement on any multitasking operating system.

A simple (though perhaps pointless, it does give a good idea of whats going on) example on the Amiga would be to write a graphics converter program, where your program does little more than run a graphical user interface. When the user selects a file to convert, say an IFF to a Jpeg, the program starts another task passes it the graphics data and then lets that task do the number crunching. The main program is now free to allow the user to do something else. Once the converter task has finished it just has to signal the main program this fact and let the user decide what to do next.

In a normal (Amiga) CPU like the 68060, each task/program is given its turn to run (I believe, assuming both tasks are at the same priority, they would switch every 12th of a second (i.e. every 4 VBL)). This just means that each program runs a bit slower than if they were running on their own.

Modern CPUs have multiple execution units which can perform the same operations (actually sometimes, like in the 68060, there is a division of abilities, but this complicates matters)... like having two calculator on your desk, this allows the CPU to run two instructions (that do not depend upon the result of each other) at the same time. A decent compiler or a good human coder, will think carefully about the order of their program's instructions to allow the CPU to do this effectivly. This is known as optimisation.

Hyperthreading, is simply a special schedualer inside the CPU which makes the single CPU core look like 2 CPU cores. So that if there is a free execution unit, ie one that the CPU couldn't fill with the currently executing task (or if the currently executing task is wating for a memory operation to complete... these take forever in CPU terms), then another program will be given a chance to use that free resource, hense using time on the CPU which otherwise would be going to waste.

The problems are many. Firstly both tasks have to share the same infrastructure... Cache, buffers, memory bus etc... secondly it's rare for a good optimised program to leave much CPU resource free.. thirdly and most importantly it requires quite a bit of silicon space to implement... and only really offers a 5 to 10 percent performance gain.

It was only useful on the "brain-dead" NetBurst architecture, and is unlikely to return in the near future. Having 2 real cores on a single die offers much greater performance gains.

bloodline wrote:

It was only useful on the "brain-dead" NetBurst architecture, and is unlikely to return in the near future. Having 2 real cores on a single die offers much greater performance gains.

Only useful on a brain-dead architecture like Netburst? That must mean Power5 is a brain-dead architecture too..

http://www-03.ibm.com/servers/eserver/iseries/perfmgmt/pdf/SMT.pdf

The IBM® POWER4™ processor introduced two processors embedded in a single chip, sharing
a common L2 level cache to increase processing efficiency. The POWER5™ processor builds on
this topology with a significant enhancement called Simultaneous Multithreading (SMT), a
concept where multiple threads of execution can execute on the same processor at the same time.