Re: [9fans] threads vs forks

[James Tomaschke <james@orcasystems.com>]

J.R. Mauro wrote:
> On Tue, Mar 3, 2009 at 7:54 PM, erik quanstrom <quanstro@quanstro.net> wrote:
>>> I should have qualified. I mean *massive* parallelization when applied
>>> to "average" use cases. I don't think it's totally unusable (I
>>> complain about synchronous I/O on my phone every day), but it's being
>>> pushed as a panacea, and that is what I think is wrong. Don Knuth
>>> holds this opinion, but I think he's mostly alone on that,
>>> unfortunately.
>> it's interesting that parallel wasn't cool when chips were getting
>> noticably faster rapidly.  perhaps the focus on parallelization
>> is a sign there aren't any other ideas.
>
> Indeed, I think it is. The big manufacturers seem to have hit a wall
> with clock speed, done a full reverse, and are now just trying to pack
> more transistors and cores on the chip. Not that this is evil, but I
> think this is just as bad as the obsession with upping the clock
> speeds in that they're too focused on one path instead of
> incorporating other cool ideas (i.e., things Transmeta was working on
> with virtualization and hosting foreign ISAs)

Die size has been the main focus for the foundries, reduced transistor
switch time is just a benefit from that.  Digital components work well
here, but Analog suffers and creating a stable clock at high frequency
is done in the Analog domain.

It is much easier to double the transistor count than it is to double
the clock frequency.  Also have to consider the power/heat/noise costs
from increasing the clock.

I think the reason why you didn't see parallelism come out earlier in
the PC market was because they needed to create new mechanisms for I/O.
  AMD did this with Hypertransport, and I've seen 32-core (8-socket)
systems with this.  Now Intel has their own I/O rethink out there.

I've been trying to get my industry to look at parallel computing for
many years, and it's only now that they are starting to sell parallel
circuit simulators and still they are not that efficient.  A
traditionally week-long sim is now taking a single day when run on
12-cores.  I'll take that 7x over 1x anytime though.

/james