🚀 go-pugleaf

In article <43700014@uicsrd> turner@uicsrd.CSRD.UIUC.EDU writes:
>At the end there you lost me; the serial bottleneck will NEVER fade
>away completely.  Some things just have to be done in order.
>Admittedly parallel processing is a good thing, but haven't you ever
>heard of Amdahl's Law?  Parafrased as: The amount of speedup due to
>paralleism in a program in inheirently limited to the reciprocal of the
>sequential fraction.  That is if a program is 99% parallelizable then
>on an unlimited number of processors (even given perfect communication) 
>the maximum possible speedup is only 100.  To achieve parallelism of
>several orders of magnitude we will have to design algorithms that
>compute in parallel more than 99.99% of the time, a difficult feat -
>but what better challenge to the modern computer scientist.
>---------------------------------------------------------------------------
> Steve Turner (on the Si prairie  - UIUC CSRD)
>
No insult to Gene Amdahl, and maybe I just don't understand something here,
but...
Didn't we already solve this problem once?  Scenario was "aaaargh, I have to go
access the disk <cpu grinds to a halt...whole milliseconds later> data!  Now I
can compute some more!".  Scenario is "arrgh, i have to go access the disk
<cpu schedules another ready job, several microseconds pass> Ah!  Now I can
work while I wait".  Seems we called this one multiprocessing.

Seems to me the same scam works for jobs that sometimes go serial.  Since you
were kind enough to provide me with unlimited processors ;-), I'll just put
enough parallel jobs running so the the jitter in resource usage due to some
jobs going serial for a while is smoothed out.  No sense in coining a new
word, we can still call this one multiprocessing.

After all, as in the earlier case, what we usually want is job _stream_
throughput, rather than _job_ throughput especially.

I do NOT volunteer to design, code, or debug the scheduling algorithm for this
one...at least not until I get really desperate for a PhD thesis topic in a few
years here.  ;-)

Basis for most of our troubles with Amdahl's Law right now is that our
supercomputers are monoprocessors or very scant multiprocessors.  Nothing like
having a hundred thousand jobs in the run queue to calm down the resource
bobbles.  ;-)
--
Kent Paul Dolan, "The Contradictor", 25 years as a programmer, CS MS Student
at ODU, Norfolk, Virginia, to find out how I was supposed to be doing this
stuff all these years.  3D dynamic motion graphics a specialty.  Work wanted.

Unemployment is soooo nice though...I never have to disclaim anything!

UUCP  :  kent@xanth.UUCP   or    ...seismo!decuac!edison!xanth!kent
CSNET :  kent@odu.csnet    ARPA  :  kent@xanth.cs.odu.edu
Voice :  (804) 587-7760    USnail:  P.O. Box 1559, Norfolk, Va 23501-1559
Wisdom:  "Peace in mankind's lifetime.  Why leave a whole universe unexpexpesdos