Mailinglist Archive: opensuse-factory (648 mails)

[Fritz Elfert <fritz.elfert@xxxxxxxxxxx>]

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On 11/02/2010 10:27 PM, Cristian Morales Vega wrote:
> Fedora 14 has been released with libjpeg-turbo
> (http://libjpeg-turbo.virtualgl.org/). I see we have multiple packages
> in home repos (home:Lazy_Kent, home:felfert, home:iboss32,
> home:mkromer and home:prusnak)... so someone can comment about this?
>
> Fedora sells this as a libjpeg API/ABI compatible changes that is just
> faster.

It's exactly that.

> From a quick look it seems to be API/ABI compatible with the
> old 6.2 version that was available for years, but 11.3 already
> provides the binary incompatible 8.0. What other distros do?
> Also, not sure if featurewise they are 100% equivalent (see
> https://bugzilla.redhat.com/show_bug.cgi?id=639672).

If you read the initial comment on that bug, the poster mentions filing
the bug against the original jpeg-62b, so yes - it is 100% compatible.
BTW, that "bug" looks more like a feature request for an algorithm that
has been left out due to legal IP problems so far.

> Finally, this probably would be mostly a x86-64 improvement? Since we
> target i586 for x86-32, that doesn't provides MMX/SSE support, the
> speed improvement seems to be limited to a "25%" there.

Even older CPUs provide MMX at least. Anyway, AFAIK libjpeg-turbo
figures out the CPU's capabilities at runtime and falls back from
optimized assembler code to the original C implementation.

In an environment where speed is essential (I'm using it with NoMachines
NX protocol - which can use jpeg for compressing bitmaps), libjpeg-turbo
is simply *perfect*. I don't have numbers, but my Application (OpenNX)
simply "feels" a *lot* faster when using libjpeg-turbo - especially when
working over slow connections.

Regarding stability: i'm using it for almost 2 years now and never had
any problems.

So, even if you get only 25% speed gain - it's worth the effort. For my
part, i'm really glad to see libjpeg-turbo getting into F14.

Just my 2 cent
 -Fritz
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