[mythtv-users] Re: Playback of Transcoded (MPEG4) file on Epia ME6000

[Ivor Hewitt]

Cheers, pretty interesting.... although it does show that -O2 is best
on an Nemehia, and theres not much between -O2, -O3 and -Os on an
Ezra. Although the inclusion of "kernel size" as a benchmark is
clearly going to favour the -Os! :)

I think its still worth benchmarking a multimedia app, like myth or
mplayer, for a real world conclusion.

However, in summary, you're not going to go far wrong by simply
choosing "-march=i586 -O2" for any EPIA.

Regards,



On 4/23/05, MagicITX <magicitx at gmail.com> wrote:
> On 4/23/05, Ivor Hewitt <ivor.hewitt at gmail.com> wrote:
> > The gcc compiler hasn't got any scheduling logic for the c3 since via
> > hasn't released that information or contributed to the gcc
> > development..... and since the c3 design is based off the old cyrix
> > dies I suspect that the 586 optimisations might be a reasonable match.
> > 
> > -Os is all very well but that just tries to pack everything into the
> > smallest space and so disables all word alignment and doesn't try to
> > optimise the code for speed. -O2 seems like a reasonable compromise
> > for the c3. It doesn't unroll loops but does do some optimisations.
> > 
> > Personally I always found "586 and -O2" gave decent performance...
> > with the added benefit I can use the same binaries on P3, C3 and C3-2
> > which helps testing and debugging (for me).
> > 
> > If I have time I might run some benchmarks with different options.
> > 
> > 
> > On 4/22/05, Devan Lippman <devan.lippman at gmail.com> wrote:
> > > I'd have to agree with Ivor's flag settings, I've found on my TC that
> > > i586 works better than C3
> > >
> > > On 4/22/05, Ivor Hewitt <ivor.hewitt at gmail.com> wrote:
> > > > On 4/22/05, Neale Swinnerton <mythtv-users.spam at isismanor.com> wrote:
> > > > > Hi,
> > > > >
> > > > > I've got a Epia ME6000 working well as a Myth frontend. I've got
> the
> > > > > XvMC playback so that watching Live TV or recordings is great (I've
> got
> > > > > a backend with 2 x Hauppauge DVB-T cards).
> > > > >
> > > > 1. I'd have thought an m6000 would struggle. Out of interest what cpu
> > > > load are you seeing in mplayer?
> > > > 2. Why are you transcoding dvb-t recordings anyway? do you really
> need
> > > > to save disk space that badly. Wouldn't you rather watch the original
> > > > quality?
> > > >
> > > > > -march=c3 -Os -fomit-frame-pointer
> > > > >
> > > > What about just -march=i586 -O2
> > > > _______________________________________________
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> > > > mythtv-users at mythtv.org
> > > > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> > > >
> > >
> > >
> > > --
> > > Thanks,
> > > Devan Lippman <devan at lippman.net>
> > >
> > _______________________________________________
> > mythtv-users mailing list
> > mythtv-users at mythtv.org
> > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> > 
> 
> I did a comparison of compiler optimization settings for the ME6000
> and M10000.  The results are mixed.  You can find the articles on
> www.magicitx.com under the VIA Epia menu -> Optimization if you're
> interested.
> 
> -- 
> Tim
> www.magicitx.com
>