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From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: [PATCH] Add Julia.
Date: Thu, 26 Mar 2015 17:58:26 +0100
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In-Reply-To: <87twx7okgn.fsf@netris.org> (Mark H. Weaver's message of "Thu, 26
	Mar 2015 11:19:04 -0400")
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To: Mark H Weaver <mhw@netris.org>
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Mark H Weaver <mhw@netris.org> skribis:

> Mark H Weaver <mhw@netris.org> writes:
>
>> Ricardo Wurmus <ricardo.wurmus@mdc-berlin.de> writes:
>>
>>> May I suggest adding passing the "DYNAMIC_ARCH=3D1" flag in openblas
>>> instead of propagating non-substitutability to Julia?  When built with
>>> "DYNAMIC_ARCH=3D1" the CPU type can be picked with the environment
>>> variable OPENBLAS_CORETYPE=3D<type>.  If I'm not mistaken this makes
>>> substitutions for openblas possible.
>>>
>>> What do you think?
>>
>> Yes, we should do this.
>
> When reading this the first time, somehow I managed to miss the fact
> that users will have to set OPENBLAS_CORETYPE to their CPU type.

Me too actually.

> Does that mean that openblas is unable to detect the CPU type
> automatically?  What does it do if OPENBLAS_CORETYPE is unset?
>
> Will we have to set it during the build of packages that use openblas,
> such as Julia?

Good points, this is a bit scary.  I assumed openblas would just detect
the CPU automatically at run time.

Ludo=E2=80=99.