[OE-core] for a quad-core machine, shouldn't parallelism be set to 8?

[Elvis Dowson]

Hi Robert,
On my i7 quad core machine, I've set both values to 6. Setting it to 6 appears to be nearly the same as setting it to 8, I dare say a marginally faster by a minute. I can build core image console in around 22 minutes.

Elvis

Sent from my iPad

On Jan 9, 2013, at 4:55 PM, "Robert P. J. Day" <rpjday at crashcourse.ca> wrote:

> 
>  just noticed this in local.conf.sample:
> 
> # For a quad-core machine, BB_NUMBER_THREADS = "4", PARALLEL_MAKE = "-j 4" would
> # be appropriate for example.
> 
>  i thought the general rule was that parallelism should be *twice*
> the number of cores.  that's certainly what's suggested in the yocto
> QS guide:
> 
> "Another couple of variables of interest are the BB_NUMBER_THREADS and
> the PARALLEL_MAKE variables. By default, these variables are commented
> out. However, if you have a multi-core CPU you might want to uncomment
> the lines and set both variables equal to twice the number of your
> host's processor cores. "
> 
>  thoughts?
> 
> rday
> 
> -- 
> 
> ========================================================================
> Robert P. J. Day                                 Ottawa, Ontario, CANADA
>                        http://crashcourse.ca
> 
> Twitter:                                       http://twitter.com/rpjday
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