GNU bug report logs - #64188
[PATCH 0/8] More package tuning

Previous Next

Full log

View this message in rfc822 format

From: Ludovic Courtès <ludo <at> gnu.org>
To: Efraim Flashner <efraim <at> flashner.co.il>
Cc: Josselin Poiret <dev <at> jpoiret.xyz>, Tobias Geerinckx-Rice <me <at> tobias.gr>, Simon Tournier <zimon.toutoune <at> gmail.com>, Mathieu Othacehe <othacehe <at> gnu.org>, Christopher Baines <mail <at> cbaines.net>, 64188 <at> debbugs.gnu.org, Ricardo Wurmus <rekado <at> elephly.net>
Subject: [bug#64188] [PATCH 0/8]  More package tuning
Date: Sun, 25 Jun 2023 22:47:42 +0200

Hello Efraim,

Efraim Flashner <efraim <at> flashner.co.il> skribis:

> with gcc-11, gcc gained support for using -march=x86_64-v{1,2,3,4},
> which I'm calling 'generic options,' as opposed to the more targeted
> tuning we have with specific architectures.

I don’t think these x86_64 psABI “architecture levels” should be treated
specially:

  • From the point of view of ‘--tune’, they’re just another value that
    may be passed to ‘-march’.

  • My understanding is that those levels don’t match reality: as
    discussed in the original ‘--tune’ patch¹, CPUs actually produced
    don’t follow a pattern of strictly including features of one set.
    They’re really just a simplification to get more memorizable names,
    but it’s hard to tell whether a given CPU really covers the set of
    features of a given level.

Overall, my take on this would be to add supported levels to
‘%gcc-11-x86_64-micro-architectures’ & co., without going further.

WDYT?

¹ https://issues.guix.gnu.org/52283#0-lineno48

[...]

> go cpu tuning targets: I mostly used the chart¹ on the go website, and I
> also checked the source code for go-1.18. I put in arm{5,6,7} as arm and
> not armhf since armhf only works with armv7 and with go programs, since
> they're statically linked, they can just be copied to other machines.

Now if Go uses those names, (guix cpu) can provide helpers.

Thanks,
Ludo’.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.