* “Tuning packages for a CPU micro-architecture”
@ 2022-01-06 16:22 Ludovic Courtès
2022-01-06 21:32 ` zimoun
0 siblings, 1 reply; 3+ messages in thread
From: Ludovic Courtès @ 2022-01-06 16:22 UTC (permalink / raw)
To: guix-science
Hello there, and happy new year where applicable!
This blog post discusses the new ‘--tune’ option and “package
multi-versioning” as a way of achieving performance without giving up on
reproducibility:
https://hpc.guix.info/blog/2022/01/tuning-packages-for-a-cpu-micro-architecture/
I’ve found reproducibility to be often depicted as being detrimental to
performance in HPC circles, so this is a contribution to suggest
otherwise.
Ludo’.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: “Tuning packages for a CPU micro-architecture”
2022-01-06 16:22 “Tuning packages for a CPU micro-architecture” Ludovic Courtès
@ 2022-01-06 21:32 ` zimoun
2022-01-07 9:46 ` Ludovic Courtès
0 siblings, 1 reply; 3+ messages in thread
From: zimoun @ 2022-01-06 21:32 UTC (permalink / raw)
To: Ludovic Courtès, guix-science
Hi Ludo,
Thanks for this nice blog post!
On Thu, 06 Jan 2022 at 17:22, Ludovic Courtès <ludovic.courtes@inria.fr> wrote:
> I’ve found reproducibility to be often depicted as being detrimental to
> performance in HPC circles, so this is a contribution to suggest
> otherwise.
Who knows if an “HPC fool” would not write a ’package-with-tune’
rewriting the ’tune’ properties to all the packages and then run a
world-rebuild. ;-)
Well, the conscious choice of letting ’--tune’ operates only on packages
explicitly marked as “tunable” appears to me a clean design. It makes a
an explicit and clear separation between “portable-optimized” packages
(almost all) vs “micro-optimized” packages. The best of both worlds: as
much as possible reproducible, sacrificing for few corner-cases, keeping
the performance for all.
Cheers,
simon
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: “Tuning packages for a CPU micro-architecture”
2022-01-06 21:32 ` zimoun
@ 2022-01-07 9:46 ` Ludovic Courtès
0 siblings, 0 replies; 3+ messages in thread
From: Ludovic Courtès @ 2022-01-07 9:46 UTC (permalink / raw)
To: zimoun; +Cc: guix-science
Hello,
zimoun <zimon.toutoune@gmail.com> skribis:
> On Thu, 06 Jan 2022 at 17:22, Ludovic Courtès <ludovic.courtes@inria.fr> wrote:
>
>> I’ve found reproducibility to be often depicted as being detrimental to
>> performance in HPC circles, so this is a contribution to suggest
>> otherwise.
>
> Who knows if an “HPC fool” would not write a ’package-with-tune’
> rewriting the ’tune’ properties to all the packages and then run a
> world-rebuild. ;-)
Heh. :-)
> Well, the conscious choice of letting ’--tune’ operates only on packages
> explicitly marked as “tunable” appears to me a clean design. It makes a
> an explicit and clear separation between “portable-optimized” packages
> (almost all) vs “micro-optimized” packages. The best of both worlds: as
> much as possible reproducible, sacrificing for few corner-cases, keeping
> the performance for all.
Yeah, I think so.
A question that remains: even as a “regular user” on my laptop, I use
things that depend for instance on Eigen. Often Eigen is not critical
to the overall performance (and energy efficiency) of those things, but
it still plays its part; it would be tempting from that perspective to
have ‘--tune’ turned on by default. I think it’s too early to take that
route but might be something to consider in the future.
Thanks for your feedback!
Ludo’.
^ permalink raw reply [flat|nested] 3+ messages in thread
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