Re: OT Dual core CPUs versus faster single core CPUs?

On Sat, 03 May 2008 15:06:53 -0700, the renowned John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Sat, 03 May 2008 13:59:50 -0700,
"MassiveProng@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
<MassiveProng@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Sat, 03 May 2008 09:20:50 -0700, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Sat, 3 May 2008 08:51:03 -0700 (PDT), rickman <gnuarm@xxxxxxxxx>
wrote:

On May 2, 11:42 pm, John Larkin
<jjlar...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
On Fri, 2 May 2008 19:11:49 -0700 (PDT), rickman <gnu...@xxxxxxxxx>
wrote:

On May 1, 8:28 pm, John Larkin
<jjlar...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

The real use for multiple cores will to be to assign one function per
core. One would be the OS kernal, and only that, and would be entirely
protected from other processes. Other cores could be assigned to be
specific device drivers, file managers, TCP/IP socket managers, things
like that. Then one core could be assigned to each application process
or thread. Only a few cores need floating-point horespower, which
might be hardware shared. Power down idle cores. Voila, no context
switching, no memory corruption, and an OS that never crashes.

Microsoft won't like it at all.

John

Good luck on that "never crashes" thing. How do you think a given CPU
will get its program?

The OS cpu will assign it a task, create its memory image, set up its
privileges, and kick it off. And snoop it regularly to make sure it's
behaving.

You are missing my point. The fact that tasks run on separate
hardware does not mean they don't share memory and they don't
communicate. You still have all the same issues that a single
processor system has. It is **very** infrequent on my system that it
hangs in a mode where I can't get control of the CPU. I am running
Win2k and I let it run for a month or more between reboots. Usually
the issue that makes me reboot is that the system just doesn't behave
correctly, not that it is stuck in a tight loop with no interrupts
enabled. So multiple processors will do nothing to improve my
reliability.


How does it know it is a device driver rather

than an application?

See above.

How does memory *not* get shared? Main memory

will never be on the CPU chip, at least not as long as they want to
keep increasing performance at a low cost.

Hardware memory management can keep any given CPU from damaging
anything but its own application space. Intel has just begun to
recognize - duh - that it's not a good idea to execute data or stacks,
or to allow apps to punch holes in their own code. Allowing things
like buffer overflow exploits is simply criminal.

So this indicates that multiple processors don't fix the problem. The
proper use of hardware memory management fixes the problem. No?


Multi CPUs is nothing new. It has been done for ages. In fact one of
the very first computers was a multi-processor machine. The problem
is that it is very hard to use many CPUs efficiently. We are bumping
up against some real limitations in CPU speed improvements. So we
have to start using multiple CPUs. But these are also inefficient.
We are reaching an age where progress will be coming slower and with
more cost and pain.

But speed is no longer the issue for most users. Reliability is. We
need to get past worrying about using every transistor, or even every
CPU core, 100%, and start making systems manageable and reliable.
Since nobody seem able to build reliability or security into complex
software systems, and the mess isn't getting any better (anybody for
Vista?) we need to let hardware - the thing that *does* work - assume
more responsibility for system integrity.

What else are we going to do with 256 CPUs on one chip?

That is the big question. I like the idea of having at least two
processors. I remember some 6 years ago when I was building my
current computers that dual CPUs on a mother board were available.
People who do the kind of work that I do said they could start an HDL
compile and still use the PC since they each had a processor. I am
tired of my CPU being sucked dry by my tools or even by Adobe Acrobat
during a download and the CPU nearly halting all other tasks. Of
course, another solution is to ditch the Adobe tools. Next to
Microsoft, they are one of the very worst software makers.

I use Foxit and CutePDF. Both fast, bulletproof, and free.



Personally, I don't think we need to continue to increase processing
at this geometric rate. Since we can't, I guess I won't be
disappointed. I see the processor market as maturing in a way that
will result in price becoming dominant and "speed" being relegated to
the same category as horsepower. The numbers don't need to keep
increasing all the time, they just need to match the size of the car
(or use for PCs). The makers are not ready to give up the march of
progress just yet, but they have to listen to the market. It will be
within 5 years that nobody cares about the processor speed or how many
CPUs your computer has. It will be about the utility. At that point
the software will become the focus as the "bottleneck" in speed,
reliability and functionality. Why else does my 1.4 GHz CPU seem to
respond to my keystrokes at the same (or slower) speed than my 12 MHz
286 from over 10 years ago? "It's the software, stupid!" :^)

Yes. So make the software, especially the OS, simpler. Vista tried
going partly towards the "small kernal" approach for reliability, but
took a big hit on performance by moving the graphics stuff out of
kernal space. If it ran in its own CPU, there would be no penalty. Any
"big kernal" OS (like Windows or Linux) will spend a lot of time
context switching, stack swapping, reloading memory management
hardware, doing interrupts, all the junk you'd not have to do if there
were a CPU per process.

Microsoft's approach to multicore is to make things more complex, not
less. Hell, Microsoft's approach to everything is to make it more
complex. Ironic that the biggest software company on the planet writes
garbage software.




who just rebooted a hung XP. Had to power cycle the stupid thing. But
I'm grateful that it, at least, came back up.

I am ready to buy a laptop and I am going to get a Dell because they
will sell an XP system rather than Vista. Everything I have heard is
that XP is at least as good as Win2K. No?

XP seems fairly solid, in most installations. Being a Microsoft
product, there are occasional systems that crash often, for no obvious
reason. XP does boot up a lot faster than 2K.

John



The word is KERNEL.

I've seen it spelled both ways. And written three myself.

John

http://www.uit.co.uk/cur/cur-pascal.txt


"Most people fail to consider that good programmers are very
bright. Their thoughts are extremely well organized and most of
them have the benefit of higher education. Their brains are not
warped by overexposure to TV and their attention spans are not
short-circuited by overindulgence in sex, drugs, or alcohol.
They are not constrained by conventionality. If you want to get
picky, there are a lot more programmers than there ever were
writers. And programmers simply work harder than writers. Few
writers work 100 hours a week; almost all programmers do."

The result, according to Wirth? "All programmers write at least
as well as Faulkner. Most are as good as Proust, and about a
third are as good as Dickens. Several hundred are at least as
good as Shakespeare. So the manuals you thought were inferior
were simply beyond your poor ability to appreciate. If you were
a programmer, you would delight in their verbal virtuosity," he
said.

In fact, Wirth claimed, even the grammatical errors and
misspellings in the manuals were placed there deliberately. Most
are elaborate literary allusions and puns; some are inventive
Joycean neologisms. As an example, Wirth discussed the history
of the word "kernal."

"Everyone, including programmers, knows the word is spelled k-e-
r-n-e-l," he explained. "The deliberate misspelling is an
implied criticism of the typesetter (a writer's bane for years.)
Of course typesetters kern the letter l; thus, `kern el'. But
kerning can only be done for certain letter combinations, such as
two l's. Thus, `kern a l' dares the typesetter to kern an
isolated l, an obvious typographic impossibility.

"Moreover," he continued, "`kernal' is an anagram for `rankle,'
which describes programmers' feelings toward typesetters.
Finally the inventor of this particular word, R. K. Lane (who is
well known within the Southern California computer community) has
concealed his name by means of yet another anagram."



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@xxxxxxxxxxxx Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
.

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