[mythtv-users] Re: HDTV, Myth, HD-2000, HD-3000, questions galore (and hopefully answers from the smart people... )

[Paul Leppert]

Brad,

My memory bandwidth is 779 MB/s (according to memtest).  I have 512MB
of RAM, but this is probably pretty old memory (PC2100, I think).

Do you think this is the problem?  Does anyone have any comparison
they can provide in terms of their performance with HDTV and an Athlon
XP 3200+ (or even less)?

I don't want to keep throwing new hardware money at the problem if it
looks like I have a bottleneck somewhere in the system.

Thanks,
phlepper


On Fri, 28 Jan 2005 00:45:38 -0800, Brad Templeton
<brad+myth at templetons.com> wrote:
> On Thu, Jan 27, 2005 at 11:46:08PM -0600, Paul Leppert wrote:
> > When watching livetv on ABC (HD 720p), I end up with 0% idle using top
> >     72% cpu usage for mythfrontend
> >     18% cpu for mythbackend
> >      6% for X
> >      1% for lirc_dev
> >     <1% for top and others
> >
> > When watching livetv on NBC (HD 1080i), I end up with 0% idle using top
> >     82% cpu usage for mythfrontend
> >      9% cpu for mythbackend
> >      7% for X
> >      1% for lirc_dev
> >     <1% for the rest
> >
> > When watching recorded Fox (no recording), I end up with 10% idle using top
> >      56% cpu usage for mythfrontend
> >      24% for mythbackend
> >       5% for X
> >       1% for lirc_dev
> >       <1% for the rest
> >
> > When watching recorded NBC (no recording), I end up with 0% idle using top
> >      85% cpu usage for mythfrontend
> >      10% for X
> >       2% for mythbackend
> >       1% for lirc_dev
> >       <1% for the rest
> >
> > These numbers seem much worse than what I've read from other people
> > online.  What are others seeing with HDTV?  Should I be getting better
> 
> Yes, they are worse.  Though actually my Athlon-3K system is currently
> doing 100% saturation because I am going through more nvidia driver
> problems and booting it without AGP, so I get saturation but all the CPU
> is in the X server.
> 
> Surprised to see much CPU in the back end, that I don't normally see
> when it's recording.  All it has to do is demux the atsc stream and write
> to disk.   Have not tried the 1.6 drivers, they reported it doesn't work
> well on 2.6.10 in the release notes for that driver.
> 
> Is it possible you have some sort of memory bottleneck?  How's your
> memory bandwidth?  Try bw_mem in lmbench or memtest86.
> 


-- 
I hear and I forget. I see and I remember. I do and I understand.  --  Confucius