From: iyzsong@member.fsf.org (宋文武)
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: guix-devel@gnu.org
Subject: Re: [PATCH 2/2] gnu: zita-convolver: Drop the '-march=native' optimization.
Date: Thu, 07 Jan 2016 22:53:45 +0800 [thread overview]
Message-ID: <8760z51lvq.fsf@member.fsf.org> (raw)
In-Reply-To: <8737u9ttjh.fsf@gnu.org> ("Ludovic Courtès"'s message of "Thu, 07 Jan 2016 14:20:50 +0100")
ludo@gnu.org (Ludovic Courtès) writes:
> Ricardo Wurmus <rekado@elephly.net> skribis:
>
>> 宋文武 <iyzsong@member.fsf.org> writes:
>>
>>> Ricardo Wurmus <rekado@elephly.net> writes:
>>>
>>>>> + (snippet
>>>>> + ;; Don't optimize for a specific processor architecture.
>>>>> + '(substitute* "libs/Makefile"
>>>>> + (("^CXXFLAGS \\+= -march=native") "")))
>>>>> + (modules '((guix build utils)))
>>>>
>>>> Is this to avoid that packages are optimised for the CPU of the build
>>>> slave?
>>> Yes, using that from hydra will crash guitarix for me.
>>> Same as: <https://bugs.archlinux.org/task/36248>.
>>
>> Guitarix also crashes for me on i686 — and I thought it was something to
>> do with my machine or the broken build of eigen.
Pushed, hopefully this will fix it on i686 too.
>
> Eigen is a header-only library, so what matters is the optimization
> flags passed when building the software that uses Eigen.
>
>>>> If so, could we instead pass different optimisation flags for
>>>> different architectures? For a convolver I’d prefer to have *some*
>>>> optimisation, even if it’s just the greatest common divisor.
>
> It’s likely that zita-convolver has -O2 or similar *in addition* to
> -march=native, because the latter is no substitute for the former.
>
> Could you check that in the makefiles?
Yes, it actually has:
CXXFLAGS =+ -ffast-math -funroll-loops -O3
prev parent reply other threads:[~2016-01-07 14:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-06 15:48 [PATCH 2/2] gnu: zita-convolver: Drop the '-march=native' optimization 宋文武
2016-01-06 21:13 ` Ricardo Wurmus
2016-01-07 3:58 ` 宋文武
2016-01-07 8:37 ` Ricardo Wurmus
2016-01-07 13:20 ` Ludovic Courtès
2016-01-07 14:53 ` 宋文武 [this message]
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