From: Ricardo Wurmus <rekado@elephly.net>
To: Pjotr Prins <pjotr.public12@thebird.nl>
Cc: guix-devel@gnu.org, Dave Love <fx@gnu.org>
Subject: Re: OpenBLAS and performance
Date: Wed, 20 Dec 2017 19:15:16 +0100 [thread overview]
Message-ID: <87d139xo3v.fsf@elephly.net> (raw)
In-Reply-To: <20171220172215.GA7926@thebird.nl>
Hi Pjotr,
> I was just stating that the default openblas package does not perform
> well (it is single threaded, for one).
Is it really single-threaded? I remember having a couple of problems
with OpenBLAS on our cluster when it is used with Numpy as both would
spawn lots of threads. The solution was to limit OpenBLAS to at most
two threads.
> If I compile for a target it
> makes a large difference.
The FAQ document[1] says this:
The environment variable which control the kernel selection is
OPENBLAS_CORETYPE (see driver/others/dynamic.c) e.g. export
OPENBLAS_CORETYPE=Haswell. And the function char*
openblas_get_corename() returns the used target.
[1]: https://github.com/xianyi/OpenBLAS/wiki/Faq
Have you tried this and compared the performance?
--
Ricardo
GPG: BCA6 89B6 3655 3801 C3C6 2150 197A 5888 235F ACAC
https://elephly.net
next prev parent reply other threads:[~2017-12-20 20:02 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-19 10:49 OpenBLAS and performance Pjotr Prins
2017-12-19 17:12 ` Ludovic Courtès
2017-12-20 11:50 ` Dave Love
2017-12-20 14:48 ` Dave Love
2017-12-20 15:06 ` Ricardo Wurmus
2017-12-22 12:24 ` Dave Love
2017-12-20 17:22 ` Pjotr Prins
2017-12-20 18:15 ` Ricardo Wurmus [this message]
2017-12-20 19:28 ` Pjotr Prins
2017-12-20 20:00 ` Ricardo Wurmus
2017-12-20 20:32 ` Pjotr Prins
2017-12-20 19:02 ` Eric Bavier
2017-12-21 16:38 ` Dave Love
2017-12-20 23:02 ` Ricardo Wurmus
2017-12-21 10:36 ` Pjotr Prins
2017-12-21 14:43 ` Ludovic Courtès
2017-12-22 14:35 ` Dave Love
2017-12-21 16:17 ` Dave Love
2017-12-21 16:46 ` Ricardo Wurmus
2017-12-21 14:55 ` Ludovic Courtès
2017-12-22 12:45 ` Dave Love
2017-12-22 15:10 ` Ludovic Courtès
2017-12-22 16:08 ` Pjotr Prins
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