Re: Embedded languages based on early Ada (from "Re: Preferred OS, processor family for running embedded Ada?")

["Dr. Adrian Wrigley" <amtw@linuxchip.demon.co.uk.uk.uk>]

On Mon, 05 Mar 2007 15:23:54 +0000, Colin Paul Gloster wrote:

> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> posted on Fri, 2 Mar
>    2007 17:32:26 +0100 :
> "[..]
> 
>> I'm looking for something like Cilk, but even the concurrent loop
>> (JPR's for I in all 1 .. n loop?) would be a help.
> 
> Maybe, just a guess, the functional decomposition rather than statements
> could be more appropriate here. The alternatives would access their
> arguments by copy-in and resynchronize by copy-out."
> 
> From William J. Dally in 1999 on
> HTTP://CVA.Stanford.edu/people/dally/ARVLSI99.ppt#299,37,Parallel%20Software:%20Design%20Strategy
> :"[..]
> - many for loops (over data,not time) can be forall
> [..]"
> Without reading that presentation thoroughly now, I remark that Dally
> seemed to be supportive of Wrigley's finely grained parallelism.

I hadn't seen that presentation, but a number of other key points
are made by Dally:
-------------------------------------
# Writing parallel software is easy
    * with good mechanisms

# Almost all demanding problems have ample parallelism

# Need to focus on fundamental problems
    * extracting parallelism
    * load balance
    * locality
          o load balance and locality can be covered by excess parallelism

Conclusion: We are on the threshold of the explicitly parallel era 
    *  Diminishing returns from sequential processors (ILP)
          o no alternative to explicit parallelism
    * Enabling technologies have been proven
          o interconnection networks, mechanisms, cache coherence
    * Fine-grain machines are more efficient than sequential machines

# Fine-grain machines will be constructed from multi-processor/DRAM chips
# Incremental migration to parallel software
-----------------------------------

Good to find *somebody* agrees with me!

Shame Ada isn't leading the pack :(
--
Adrian