From: zimoun <zimon.toutoune@gmail.com>
To: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Cc: 51536@debbugs.gnu.org
Subject: bug#51536: openblas builds not reproducible on different x86_64 machines
Date: Wed, 3 Nov 2021 16:03:04 +0100 [thread overview]
Message-ID: <CAJ3okZ2H=_MuXqU4_NjqC0LSZqi9pLJBDr+xN6pZ25zWnpzvFQ@mail.gmail.com> (raw)
In-Reply-To: <87h7cw7ewb.fsf@gmail.com>
Hi Maxim,
On Mon, 1 Nov 2021 at 04:08, Maxim Cournoyer <maxim.cournoyer@gmail.com> wrote:
> Our OpenBLAS package uses DYNAMIC_ARCH=1 to provide optimizations for
> all supported targets, at least of x86 and x86_64. In theory that seems
> OK, but in practice the builds differ depending on the host CPU.
>
> I've made a build on an old Core2 CPU (Q6700), and another one on
> Berlin. I've run diffoscope on the result, and got tons of differences;
> here's the tail of the diffoscope output:
Well, it rings this bell [1] and this one [2] too. ;-)
Maybe I am wrong, but speaking about HPC, it seems expected that the
builds differ depending on the host CPU and I am not convinced we can
do better than DYNAMIC_ARCH=1 for performances which somehow sacrifice
reproducibility, IIUC.
1: <https://hpc.guix.info/blog/2018/01/pre-built-binaries-vs-performance/>
2: <https://hpc.guix.info/blog/2019/12/optimized-and-portable-open-mpi-packaging/>
Cheers,
simon
next prev parent reply other threads:[~2021-11-03 15:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-01 3:07 bug#51536: openblas builds not reproducible on different x86_64 machines Maxim Cournoyer
2021-11-01 8:54 ` Efraim Flashner
2021-11-05 16:38 ` Maxim Cournoyer
2021-11-07 2:33 ` Maxim Cournoyer
2021-11-03 15:03 ` zimoun [this message]
2022-02-02 23:13 ` Ludovic Courtès
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