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From: Warren <ve3wwg@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: Threadpool with priority version 1.1 ...
Date: Thu, 25 Mar 2010 17:21:05 +0000 (UTC)
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Maciej Sobczak expounded in news:7794a413-34e9-4340-abcc-a6568246fc38
@h18g2000yqo.googlegroups.com:

> On 24 Mar, 17:40, Warren <ve3...@gmail.com> wrote:
> 
>> Another barrier I see to this is the high cost of
>> starting a new thread and stack space allocation.
> 
>> Somehow you gotta make thread startup and shutdown
>> cheaper.
> 
> Why?
> 
> The problem of startup/shutdown cost and how many cores you have are
> completely orthogonal.
> I see no problem in starting N threads at the initialization time, use
> them throughout the application lifetime and then shut down at the end
> (or never).

Yes, I am aware of that option.

> If your favorite programming model involves lots of short-running
> threads that have to be created and torn down repeatedly, then it has
> no relation to multicore. It is just a bad resource usage pattern.
> Maciej Sobczak * http://www.inspirel.com

That's a rather sweeping statement to make ("bad resource usage
pattern"). Unless there are leaps in language design, I believe
that is what you will mostly get in automatic parallel thread
generation.

As humans we tend to think in sequential steps, and consequently
code things. The media seems to suggest that we shouldn't have 
to change our mindset to do parallism (i.e. the compilers should 
arrange it for us). Certainly that would make a wish list item.

I don't know much about Intel's hyper-threads, but I believe it
was one approach to doing this (presumably largely without
compiler help).

So I can't buy into your conclusion on that.

Warren