From: "Ludovic Courtès" <ludo@gnu.org>
To: Leo Famulari <leo@famulari.name>
Cc: 51198@debbugs.gnu.org, "Nicolò Balzarotti" <anothersms@gmail.com>
Subject: [bug#51198] [PATCH] gnu: Add b2sum.
Date: Wed, 27 Oct 2021 17:56:31 +0200 [thread overview]
Message-ID: <875ytifols.fsf_-_@gnu.org> (raw)
In-Reply-To: <YXlyYGZAOg7GhC5m@jasmine.lan> (Leo Famulari's message of "Wed, 27 Oct 2021 11:38:08 -0400")
Hi!
Leo Famulari <leo@famulari.name> skribis:
> On Wed, Oct 27, 2021 at 10:44:45AM +0200, Nicolò Balzarotti wrote:
>> This blog post [fn:1] on guix-hpc address the "Pre-built binaries
>> vs. performance" dilemma.
>>
>> [fn:1] https://hpc.guix.info/blog/2018/01/pre-built-binaries-vs-performance/
>
> It's helpful, but it doesn't look like we are using that method in Guix
> anymore. It was removed in this commit:
>
> https://git.savannah.gnu.org/cgit/guix.git/commit/?id=969adb235ee34decb65255e1ea821ff0e221ed3d
>
> I guess it learned how to do runtime feature detection?
BLIS has run-time/load-time feature detection now (which is the main
approach the blog argues for).
>> I guess the easiest way is to provide a variant (b2sum-avx or something
>> like that) with avx enabled. Else, I'd just go with the unoptimized
>> version as it happens for many other packages, but let's hear from
>> others.
>
> The easiest thing is require local building, since it's an extremely
> cheap build. Only 1.5 seconds on my laptop, total (not just the build
> phase). With blis, one had to consider the lengthy build time.
>
> Because performance is critical for a tool like this, and because it's
> cheap to build, I've attached a patch to require local building. This is
> easier for me than creating a set of package variants that will need to
> be expanded for each new generation of CPUs :)
>
>>From 8b862425310cf631c30c823eb0fa2bfd79d36823 Mon Sep 17 00:00:00 2001
> From: Leo Famulari <leo@famulari.name>
> Date: Wed, 27 Oct 2021 11:29:40 -0400
> Subject: [PATCH] gnu: b2sum: Build on the local machine.
>
> * gnu/packages/crypto.scm (b2sum)[arguments]: Set '#:substitutable? #f'.
> ---
> gnu/packages/crypto.scm | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/gnu/packages/crypto.scm b/gnu/packages/crypto.scm
> index 3acd147f25..de8bcf1d70 100644
> --- a/gnu/packages/crypto.scm
> +++ b/gnu/packages/crypto.scm
> @@ -858,9 +858,18 @@ (define-public b2sum
> (base32 "04z631v0vzl52g73v390ask5fnzi5wg83lcjkjhpmmymaz0jn152"))))
> (build-system gnu-build-system)
> (arguments
> - `(#:make-flags (list (string-append "CC=" ,(cc-for-target))
> - (string-append "PREFIX=" (assoc-ref %outputs "out")))
> + `(;; By default, b2sum uses the compiler to generate instructions
> + ;; tailored to the CPU of the running machine, using "-march=native".
> + ;; This gives a ~1.5x speedup on a Core i5-6300U with a large dataset
> + ;; paged in, whereas compilation of b2sum takes ~1.5 seconds.
> + ;; b2sum does not support run-time feature detection:
> + ;; https://github.com/BLAKE2/BLAKE2/issues/1
> + ;; For more information, see the discussion beginning here:
> + ;; https://debbugs.gnu.org/cgi/bugreport.cgi?bug=51198#13
> + #:substitutable? #f
It’s okay but not entirely sufficient: on a cluster setup, you typically
talk to a daemon that’s on another machine, so the CPU features it’ll
detect there may be different from those you’ll use. Likewise, as
discussed on IRC, you’d also need #:local-build? #t.
Anyway, I’d suggest using ‘guix hash -H blake2s-256’ or similar (it uses
libgcrypt, which does the right thing). I think the latest Coreutils
provide a generic ‘cksum’, too, that probably does the right thing.
Ludo’.
next prev parent reply other threads:[~2021-10-27 16:59 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-14 4:28 [bug#51198] [PATCH] gnu: Add b2sum Leo Famulari
2021-10-26 16:07 ` bug#51198: " Leo Famulari
2021-10-26 22:26 ` [bug#51198] " Nicolò Balzarotti
2021-10-26 22:53 ` Leo Famulari
2021-10-26 22:54 ` Leo Famulari
2021-10-26 23:16 ` Leo Famulari
2021-10-27 8:44 ` Nicolò Balzarotti
2021-10-27 15:38 ` Leo Famulari
2021-10-27 15:56 ` Ludovic Courtès [this message]
2021-11-03 17:32 ` Leo Famulari
2021-11-06 16:45 ` Ludovic Courtès
2021-11-27 23:36 ` Leo Famulari
2022-03-18 17:12 ` bug#51198: " Leo Famulari
2021-11-27 23:32 ` [bug#51198] [PATCH v2 1/2] build-system/gnu: Add #:local-build? parameter Leo Famulari
2021-11-27 23:32 ` [bug#51198] [PATCH v2 2/2] gnu: b2sum: Build on the local machine Leo Famulari
2021-12-01 15:34 ` [bug#51198] [PATCH] gnu: Add b2sum zimoun
2021-12-01 17:50 ` Leo Famulari
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