[Buildroot] libmad and AVR32 optimisations

Gilles Talis gilles.talis at gmail.com
Thu Feb 21 01:48:32 UTC 2013


Dear Benoit,

2013/2/20 Benoît Thébaudeau <benoit.thebaudeau at advansee.com>
>
> Dear Gilles,
>
> Please always Cc the mailing list, use plain text (no HTML), and format your
> answers using bottom posting:
> http://en.wikipedia.org/wiki/Posting_style#Bottom-posting
>
> On Thursday, February 21, 2013 12:41:12 AM, Gilles Talis wrote:
> > Dear Benoit,
>
> > Thanks for your answer.
> > This was my initial thought: fix the package options. I agree with you that
> > it is easier.
> > But then I realized that it might be cleaner to fix the patch itself.
>
> > Still my question remains: is it worth it? Who, beside autobuilder, will
> > actually use such a configuration (build libmad on AVR32 without
> > architecture-specific optimizations).
>
> It is up to BuildRoot maintainers to decide. But I have already used this patch
> on AVR32, and the performance is too low without it to be able to do interesting
> things in parallel, so I don't think that any AVR32 user would be interested in
> libmad without enabling these optmizations, all the more the audio quality with
> these optimizations is still excellent.
>
> It's not like on ARM for which some settings produce distorted audio with some
> MP3s, so here all the settings make sense.
>
> > Thanks
> > Gilles.
>
> > 2013/2/20 Benoît Thébaudeau < benoit.thebaudeau at advansee.com >
>
> > > Dear Gilles,
> >
>
> > > On Wednesday, February 20, 2013 11:58:29 PM, Gilles Talis wrote:
> >
> > > > All,
> >
>
> > > > There is small issue in the AVR32 optimization patch [1]. This is root
> > > > cause
> >
> > > > for autobuild failures: e01f5a5484299dce1797966445f3972583c67b22 and
> >
> > > > 7ed0563fbbfc19c93ec5be35d3b6a95e496b4c5d.
> >
>
> > > > Reason is that some fixed-point math routines are implemented in
> >
> > > > architecture-specific files. If "architecture-specific optimizations"
> > > > option
> >
> > > > is disabled from the build configuration, these routines are not
> > > > compiled,
> >
> > > > but libmad is built with references to these functions though.
> >
>
> > > > My question is: is this issue worth fixing? I assume that libmad users
> > > > will
> >
> > > > usually enable all possible architecture-specific optimizations.
> >
>
> > > > Thanks
> >
> > > > Gilles.
> >
>
> > > > [1] package/libmad/libmad-0.15.1b-optimization.patch.avr32
> >
>
> > > This patch was clearly made for specific libmad settings. Rather than
> > > fixing
> > > it,
> >
> > > it would be easier to simply add a "depends on !BR2_avr32" to the config
> > > options
> >
> > > that fail on AVR32.
>
> Best regards,
> Benoît

All apologies. I didn't realize I had not copied the list in my
message. I should be more careful next time.
And also thanks for the formatting tips.

Thanks for your answer on libmad and AVR32. It confirms my thoughts.

Regards,
Gilles.


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