[Interest] how to run 21 threads concurrently

Thiago Macieira thiago.macieira at intel.com
Thu Oct 4 16:16:41 CEST 2012


On quinta-feira, 4 de outubro de 2012 16.04.41, Bo Thorsen wrote:
> Den 04-10-2012 15:51, Thiago Macieira skrev:
> > On quinta-feira, 4 de outubro de 2012 15.46.57, André Somers wrote:
> >> If you think that running 21 threads on an 8 core system will run make
> >> your task go faster, then Thiago is right: you don't understand your
> >> problem.
> > 
> > If you run 8 threads on an 8-core system and they use the CPU fully, then
> > you're running as fast as you can.
> 
> That might not be the case because he said the threads are writing to
> disk. I/O use could mean that #threads > #cores is faster. But if the
> computations are heavy enough, this could be wrong. Depends on what the
> code does.

Ah, yes, but note the "they use the CPU fully" and "all threads are ready to 
be executed" in the other paragraph. :-)

> That said, I'd be surprised if he actually did understand the problem
> completely, based on the question :P
-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center
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