[mythtv-users] Re: HDTV, Myth, HD-2000, HD-3000,
questions galore (and hopefully answers from the smart people... )
Paul Leppert
phlepper at gmail.com
Fri Jan 28 17:06:33 EST 2005
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
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