[mythtv-users] Fedora with Jarod's instructions?

[Jarod C. Wilson]

On Dec 12, 2003, at 16:06, steve at nexusuk.org wrote:

> On Thu, 11 Dec 2003, Jarod C. Wilson wrote:
>
>> The stock Fedora kernel already has the low latency patch, not sure
>> about the preempt patch. I'm contemplating trying Arjan's 2.6-test
>> kernels out of his apt repo myself...
>
> The stock Fedora kernel does indeed have the lowlatency patch, but not 
> the
> preempt patch.  The preempt patch seems to help things a lot.

Like Axel said, care to try patching that into his kernel also? :)

> I did try Arjan's 2.6 kernel and I found the performance of Myth under 
> it
> absolutely abysmal, so I'm keeping clear of 2.6 on my Myth box ATM.

Hm... Guess I'll just steer clear of that for now also... :-\

>> How "huge" is this difference between the stock FC kernel and your 
>> own?
>
> A very marked improvement - watching LiveTV (RTJpeg, quality 200 with 
> PCM
> audio) was really bad under the stock kernel - lots of dropped frames,
> frequently a complete loss of AV sync, etc.  Now it's almost flawless
> (having a problem with playback freezing for a few seconds sometimes 
> ATM
> but I don't think that's kernel related).

Ah, I'm seeing a few major differences in our setups... I'm using 
hardware encoder cards, so much less CPU demand to begin with, no AV 
sync issues, etc.

>> Also, what hardware are you seeing the "huge" difference on? I'm
>> doubtful the instantaneity of my Athlon XP 2600 will get any more
>> instantaneous. :) I believe the real benefits will show better on
>> lesser hardware.
>
> :)
> I'm running a Athlon XP 2000+ with BTTV card, outputting onto the 
> onboard
> S3 ProSavage VGA card.

Athlon XP 2600 w/PVR-250 and AVerMedia M179, outputting w/64MB GeForce 
4 MX.

> (I decided to not go above the 2000 to keep the
> temperature (and fan noise) down

Well, mine's near dead silent even with all that... But anyhow, I've 
got more CPU power, a faster video card and hardware encoders. So not 
just a case of lesser hardware, but also more CPU demand, so I guess I 
can see how the preempt patch could help out more in your situation. 
I'd still like to try it out myself, though. I think I've got a spare 
PIII-800 at work I could do some experimenting on (along with a bttv 
card, to really stress-test it)...

> also I'm thinking of getting a PVR 250
> at some point so CPU usage won't be such an issue then anyway).

Well worth it. :)

> I'm still running Myth 0.12, so an upgrade to 0.13 is on the cards this
> weekend, and I've got been given some technical data on the VGA card so
> hopefully I can add vblank interrupt support to the DRM driver this
> weekend too and get Myth syncing with the vblank properly.

Is that a ProSavage 4, 8, DDR? I have a board with a DDR, and the video 
flat-out sucks. Incredibly unimpressive and very NOT savage, by 
comparison to either an nVidia or ATi card. (I think it *might* be on 
par with a TNT2...)

Upgrading my production system to 0.13 right now...

-- 
Jarod C. Wilson, RHCE

Got a question? Read this first...
     http://catb.org/~esr/faqs/smart-questions.html
MythTV, Red Hat Linux 9 & ATrpms documentation:
     http://pvrhw.goldfish.org/tiki-page.php?pageName=rh9pvr250
MythTV Searchable Mailing List Archive
     http://www.gossamer-threads.com/archive/MythTV_C2/
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