[Numpy-discussion] Default builds of OpenBLAS development branch are now fork safe

[Olivier Grisel]

2014-03-26 22:31 GMT+01:00 Julian Taylor <jtaylor.debian at googlemail.com>:
> On 26.03.2014 22:17, Olivier Grisel wrote:
>>
>> The problem with ATLAS is that you need to select the number of thread
>> at build time AFAIK. But we could set it to a reasonable default (e.g.
>> 4 threads) for the default windows package.
>>
>
> You have to set the number of threads at build time with OpenBlas too.
> At runtime it then selects the number of online cpus but limited to the
> build time maximum.
> It defaults to the maximum of the machine it was built on. You need to
> explicitly override that for generic binaries. (I think debian binaries
> uses 64 which is probably reasonable for non MIC systems)

Yes, the official windows binary for OpenBLAS is also build with a
maximum number of threads of 64 (NUM_THREADS=64) which I find
reasonable since the runtime number of threads will be capped by the
actual number of cores.

For ATLAS I don't think there is a runtime cap, or is there?

-- 
Olivier
http://twitter.com/ogrisel - http://github.com/ogrisel