[mythtv-users] Fast CPU, DMA enabled on HD, Xv enabled, still getting pauses in Live TV

Tue Aug 19 21:22:01 EDT 2003

Another responce indicates that it might be an issue
with the signal strength.  It's worth looking into.

I first tried reducing the resolution to 352x480, and
that seemed to work well, only rebuffering about three
times in an hour and a half.

Now, here's the kicker...  I dropped the resolution to
320x480, and the number rebuffering messages went up
quite a bit (about 10 in 15 minutes).  Even more of a
kicker, top shows that mythfrontend and mythbackend
are taking up less than 10% of the CPU time
(combined), and my ide CPU (according to top) is
showing 90+%.  Everything else (including X) is less
than 1%, many of them fractional (i.e. X uses 0.1%).

So, why the heck am I dropping frames, I don't get it?
 Guess it's time to kill services and try to
optimize...

-- Joe

--- Albert Santoni <GameGod at sympatico.ca> wrote:
> Joe,
> 
> For the record, I would like to note that I have the
> same problem.
> I previously had a P3-500mhz that would pop in
> LiveTV quite often (cpu
> wasn't fast enough.)
> I upgraded to an Athlon XP 2000+, and now I get the
> pop about once every ten
> minutes, just like you do.
> The only thing I didn't swap out was my hard drives
> and PSU.
> (I also think MythTV 0.11 helped it a bit...  I
> think just the audio
> stutters now...  I may be wrong.)
> 
> Sounds like we have the same problem.
> (I've tried all the things you did - DMA, etc.)
> 
> Please let me know if you find a fix, and I'll keep
> trying to help you
> troubleshoot.
> 
> Thanks,
> 
> Albert Santoni
> 
> 
> ----- Original Message -----
> From: "Joe V" <joevph at yahoo.com>
> To: "Discussion about mythtv"
> <mythtv-users at mythtv.org>
> Sent: Tuesday, August 19, 2003 1:01 PM
> Subject: Re: [mythtv-users] Fast CPU, DMA enabled on
> HD, Xv enabled,still
> getting pauses in Live TV
> 
> 
> > Albert,
> >
> > With this particular motherboard, I did not,
> however,
> > with the previous motherboard that I was using
> (same
> > Athlon XP 2400+, DDR266), I did leave the default
> > compilation options and still had the same
> problems.
> >
> > I will probably try with a different power supply
> and
> > hard drive (the only two components not swapped
> out)
> > and see what happens.
> >
> > Thanks,
> > Joe
> >
> > --- Albert Santoni <GameGod at sympatico.ca> wrote:
> > > Did you try compiling without -march=athlon-xp?
> > > Just leave it at the default (i586??)...
> > >
> > > Someone had a similar problem, and this was the
> > > case.
> > >
> > > ----- Original Message -----
> > > From: "Joe V" <joevph at yahoo.com>
> > > To: "Discussion about mythtv"
> > > <mythtv-users at mythtv.org>
> > > Sent: Tuesday, August 19, 2003 3:44 AM
> > > Subject: Re: [mythtv-users] Fast CPU, DMA
> enabled on
> > > HD, Xv enabled,still
> > > getting pauses in Live TV
> > >
> > >
> > > > Okay, now I'm starting to go nuts.  I've gone
> > > through
> > > > the mailing-list archive, and have tried all
> sorts
> > > of
> > > > things.  Changing DMA parameters, recompiling
> > > MythTV
> > > > with -march=xthlon-xp, trying "nice" on
> > > mythbackend,
> > > > and several other things.  And I'm still
> getting
> > > > skips, and with this hardware, I don't see how
> I
> > > could
> > > > be having problems.  All I want to do is run
> > > > mythbackend and mythfrontend on the same PC
> > > without
> > > > stuttering in the video/audio.
> > > >
> > > > Perhaps based on my hardware/software setup,
> > > somebody
> > > > can make some additional recommendations.
> > > >
> > > > Hardware:
> > > > - Albatron KX400-8X motherboard (brought the
> ECS
> > > board
> > > > back to Fry's, too many problems) - VIA KT400
> > > chipset
> > > > - Athlon XP 2400+ CPU (2GHz real speed, 266MHz
> > > FSB)
> > > > - 512MB RAM (DDR333) - the BIOS indicates that
> the
> > > RAM
> > > > is running at 133MHz * 2.5 (333MHz)
> > > > - Matrox G400 Dual-Head (hooked up to a
> monitor,
> > > so
> > > > using Xv)
> > > > - Western Digital Hard Drive UDMA 100
> > > > - Soundblaster Live! 5.1 (using in full-duplex
> > > mode
> > > > with kernel drivers)
> > > > - Leadtek Winfast TV 2000 XP (I put in
> gbuffers=8)
> > > > - Tulip clone Ethernet card (no onboard NIC)
> > > >
> > > > Software:
> > > > - Red Hat Linux 9
> > > > - Recompiled the kernel, Linux-2.4.21,
> included
> > > the
> > > > low-latency and preempt patch
> > > > (/proc/sys/kernel/lowlatency shows 1)
> > > > - Before compiling any software, I set CFLAGS
> and
> > > > CPPFLAGS to -march=athlon-xp
> > > > - MythTV 0.11
> > > > - Killed off as many of Red Hat's services as
> > > possible
> > > > - Using twm as the window manager.
> > > >
> > > > hdparm -Tt shows:
> > > > /dev/hda:
> > > >  Timing buffer-cache reads:   128 MB in  0.41
> > > seconds
> > > > =312.20 MB/sec
> > > >  Timing buffered disk reads:  64 MB in  1.42
> > > seconds =
> > > > 45.07 MB/sec
> > > >
> > > > I'm using ext3 filesystems for everything, two
> > > > partitions, one for root, one for /home. which
> is
> > > > where MythTV files are stores (using symlinks
> from
> > > > /mnt/store).  The ext3 filesystem is mounted
> with
> > > > noatime, and in grub.conf, I put in
> > > > rootflags=data=writeback.
> > > >
> > > > I'm not really stressing things out, I'm
> recording
> > > > RTJPEG at 480x480, MP3 quality 7.  Switching
> to
> > > MPEG4
> > > > (as suggested in a post in the mailing-list)
> > > didn't
> > > > help any.  I have plenty of CPU time (it never
> > > goes
> > > > higher than 50% user, never less than 30%
> idle.
> > > Not
> > > > using jitter control, not using experimental
> A/V
> > > sync,
> > > > just using the default options.
> > > >
> > > > The only thing that I can think might possibly
> > > causing
> > > > some problems is that I have only one hard
> drive
> > > for
> > > > everything.  Either that, or I do I need a
> real
> > > 2.4GHz
> > > > machine (i.e. Intel?)
> > > >
> > > > Please folks, any suggestions?  Any at all?
> > > >
> > > > -- Joe
> > > >
> > > > --- Joe V <joevph at yahoo.com> wrote:
> > > > > Brian,
> > > > >
> > > > > Well, it helps a bit...  I upgraded to bttv
> > > 0.7.107
> > > > > (and specigied gbuffers=10), put my hard
> drive
> > > and
> > > > > DVD-ROM on seperate cables (don't know if
> that
> > > will
> > > > > help much), as well as forcing 32-bit
> > > operations,
> > > > > and
> 
=== message truncated ===

__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
http://sitebuilder.yahoo.com