Re: [f-cpu] Winograd DCT on my seul.org account

["Christophe" <christophe.avoinne@laposte.net>]

> >I'm speaking about parallel execution per instruction, not per thread
> >(instructions in a thread are still serialized). So long as we get no real
cpu
> >able to execute parallel instructions, there is no real gain for anything
for a
> >true parallelism. Yes, a parallel language is okay to see what is
independent
> >(the good point) and shall be surely better than C but we will still have a
lot
> >of overhead due to the use of multithreading (stack space and switching for
> >example). So if a CPU has power enough, we tend to use it more in serial way
> >than parallel way since there is no real reason to think a multithreading
would
> >*ALWAYS* run better.
>
> What do you mean by better? It may not be faster at all on
> a single processor due to the extended overhead. But there
> is one advantage compared to sequential programming. The
> parallel threads could communicate with each other in new
> ways if you think of each thread as a unique entity...

well, yes I mean faster. You're also right at some extent regarding with the
ways threads can communicate, but for the same result, you have likely a slower
execution and more wasted ressources in space too (stacks, and other structures
need space).

But okay we are off-topic, we shouldn't waste our time in such discussion.
Sorry if i'm still off-topic  :(.





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