Default value for numCapabilities?

Bulat Ziganshin bulat.ziganshin at
Tue Apr 27 12:45:14 EDT 2010

Hello Dimitry,

Tuesday, April 27, 2010, 8:09:49 PM, you wrote:

a few months ago i asked SimonM about using all cores by default, but
he said that it dramatically reduces performance in some cases

> Hi,

> As a followup to the discussion [1] about the portable way to find the
> number of CPUs/cores: how is the default value of numCapabilities [2]
> set when +RTS -N is not on the command line?

> Does GHC runtime figure out the number of cores itself, or it is by
> default 1 unless specified on the command line?

> Thanks.

> ---------------------------
> [1]
> [2]

Best regards,
 Bulat                            mailto:Bulat.Ziganshin at

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