Re: [PATCH] configure: Check bzip2 is available

From: Aleksandar Markovic <aleksandar.m.mail@gmail.com>
To: Thomas Huth <thuth@redhat.com>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
	"Daniel P . Berrange" <berrange@redhat.com>,
	"QEMU Trivial" <qemu-trivial@nongnu.org>,
	"Laszlo Ersek" <lersek@redhat.com>,
	"QEMU Developers" <qemu-devel@nongnu.org>,
	"Wainer dos Santos Moschetta" <wainersm@redhat.com>,
	"Gerd Hoffmann" <kraxel@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@redhat.com>
Subject: Re: [PATCH] configure: Check bzip2 is available
Date: Mon, 11 Nov 2019 14:33:39 +0100	[thread overview]
Message-ID: <CAL1e-=jOcLGdMM0vzdCxXHuu3cBp=VX9vkaxp7GPQZQtTF52FQ@mail.gmail.com> (raw)
In-Reply-To: <ac065856-56e2-bceb-851c-a9c150068e71@redhat.com>

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On Monday, November 11, 2019, Thomas Huth <thuth@redhat.com> wrote:

> On 08/11/2019 18.10, Peter Maydell wrote:
> > On Fri, 8 Nov 2019 at 17:07, Philippe Mathieu-Daudé <philmd@redhat.com>
> wrote:
> >> On 11/8/19 4:43 PM, Eric Blake wrote:
> >>> bzip2 is no longer a favored compression.  If we are trying to pick a
> >>> compression that is most likely to be present on any system, go with
> >>> gzip.  If we are trying to pick a compression that packs tighter and
> >>> uncompresses faster, pick xz or zstd.  But bzip2 does neither: it packs
> >>> slightly tighter than gzip but has slower performance in doing so, and
> >>> thus is no longer used as a default compression.
> >>
> >> The problem was with OpenBSD 6.1 which hadn't xz available.
> >>
> >> In commit 12745eaa02 Gerd updated the VM to OpenBSD 6.5 and we now have
> >> access to xz. IIRC OSX supported versions also provide xz.
> >>
> >> If we want to revert Laszlo's patches and apply his first version (using
> >> xz), we should do that during 5.0 dev cycle, now it is too late.
> >> I'd prefer we simply fix bzip2 for the next release.
> >
> > I don't think we should try to use 'xz' because I don't see
> > the point. We should use something that's generally available,
> > whether that's bzip2 or gzip. Life's too short to deal with
> > yet another file compression tool and format.
>
> FWIW, on the weekend, I accidentially came accross this page:
>
>  https://www.nongnu.org/lzip/xz_inadequate.html
>
> After reading that, I also don't think anymore that we should switch to
> 'xz'.

Off topic, but, from the page you linked to:

There are two ways of constructing a software design: One way is to make it
so simple that there are obviously no deficiencies and the other way is to
make it so complicated that there are no obvious deficiencies. The first
method is far more difficult.
-- C.A.R. Hoare

Perfection is reached, not when there is no longer anything to add, but
when there is no longer anything to take away.
-- Antoine de Saint-Exupery

Perhaps we should display these quotes at some highly visible place on our
dev QEMU website. ;)

Aleksandar

>
>  Thomas
>
>
>

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