In last couple of decades the exponential increase in computer
performance was because of the advancements in both computer
architecture and fabrication technology.
What will be the case for future ? Can I comment that the next major
leap in computer performance will not because of breakthroughs in
computer architecture but rather from new underlying technology ?

On Thu, 15 Oct 2009 05:44:29 +0100, Jean <alertjean at (no spam) rediffmail.com> wrote:

In last couple of decades the exponential increase in computer
performance was because of the advancements in both computer
architecture and fabrication technology.


Call me cynical, but I can't think of any advances in computer
architecture that have entered the mainstream in the last twenty years.
Surely its *all* been in fabrication.

Yes, but utimately boring and really just rearranging the deck chairs.
Compared to the 70's and 80's the pace of development is essentially
static.

Name one feature introduced in the 80s which you consider not
"rearranging the deck chairs". For extra credit identify the
architecture in the 50s and 60s which first used this feature (or a
variant).

In last couple of decades the exponential increase in computer
performance was because of the advancements in both computer
architecture and fabrication technology.
What will be the case for future ? Can I comment that the next major
leap in computer performance will not because of breakthroughs in
computer architecture but rather from new underlying technology ?

EricP wrote:
Daniel A. Jimenez wrote:
...
Trace cache is another more-or-less recent microarchitectural innovation
that allowed Pentium 4 to get away with decoding one x86 instruction
per cycle and still have peak IPC greater than 1.

Actually trace cache goes back to the VAX HPS, circa 1985.
They called the decoded instruction cache a "node cache".
As far as I know, VAX HPS was never built though.

Sorry, no.

The HPS (and HPSm) node cache was not a trace cache. It did not have a
single entry point for a trace of instructions.

I invented the trace cache, or at least the term "trace cache", while
taking the first Wen-Mei Hwu (the H in HPS) taught after receiving his
Ph.D. and coming to UIUC in 1986 or 1987. I invented it to solve the
problems that a decoded instruction cache had with variable length
instructions (and also to support forms of guarded execution, what would
now be called control independence or hammocks or hardware if
conversion). Wen-mei was my MS advisor. I am sure that he would have
informed me if the trace cache was just the node cache rehashed (and
given me a bash, and thrown it in the trash, and not given me any cash).

Alex Peleg and Uri Weiser may have preceded me in inventing the trace
cache, and certainly patented it first. (I never patented anything at
UIUC, or prior to Intel.) But so far as I know, I invented the term
"trace cache", and popularized it at Intel in 1991, before Peleg and
Weiser.

In last couple of decades the exponential increase in computer
performance was because of the advancements in both computer
architecture and fabrication technology.
What will be the case for future ? Can I comment that the next major
leap in computer performance will not because of breakthroughs in
computer architecture but rather from new underlying technology ?

Once upon a time there was an attempt to satisfy "the aims of science /
pursuit of excellence".
It was called Itanium. Turned out to be a multi-billion dollar flop.

I think that the human brain points out the capabilities of
relatively slow computation, albeit with complex elements and high
connectivity.

On Oct 15, 12:44=A0am, Jean <alertj... at (no spam) rediffmail.com> wrote:
In last couple of decades the exponential increase in computer
performance was because of the advancements in both computer
architecture and fabrication technology.
What will be the case for future ? Can I comment that the next major
leap in computer performance will not because of breakthroughs in
computer architecture but rather from new underlying technology ?

Here's the real deal.

As my friend, whom I otherwise respect, says, the discovery of
computers was one of the most signal events in human history, perhaps
the most important since the discovery of writing. Ask anyone in the
business.

Everyone recognized that reality, and the smartest intellects ever,
including the dead and the as yet to be born, were conjured, and
everything that could be done was done in the first six days. Ask
anyone in the business. They were there.

"Andy \"Krazy\" Glew" <ag-news at (no spam) patten-glew.net> wrote:
I think that the human brain points out the capabilities of
relatively slow computation, albeit with complex elements and high
connectivity.

Of course everyone ignored my suggestion that old architects might
want to try reading some new cellular biology texts, but I think
there are many interesting sources for inspiration there. Like the
fact that you can have interconnect that requires zero energy, etc.

G.

so I naturally wonder,
what's happened in the meantime ?.

MIT built RAW and UT Austin built TRIPS.  These are really weird
architectures and microarchitectures that could be very influential
for future processors.

I tried googling "MIT RAW" and "UT Austin TRIPS" and got no hits, could
you find some links, there are a bunch of comp.arch readers that would
love to learn more.

There are certainly aspects of this whimsical algorithmic flexibility
that jar: how can it possibly take a dual core computer with billions of
instructions per second up its sleve *many seconds* to pull up the
"recently used documents" menu, every time?