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Unexplainable high CPU while watching MPEG2 with NVidia TV-out

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thomas at boerkel

Jan 5, 2005, 10:49 AM

Post #1 of 13 (4008 views)
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Unexplainable high CPU while watching MPEG2 with NVidia TV-out

HI!

Using NVidia 6629 TV-out with XV for playback in mythfrontend, I get:

- 1% CPU for mythfrontend
- 40% CPU for X

But total CPU is at 80%, causing prebuffering pause every now and then
(and all the time, if I enable kernel deint in addition).

Strange is, I can't see any other process with "top", that takes the
rest of the CPU (the other 40%).

Watching LiveTV without prebuffering pause is impossible, because that
adds another 10% CPU, reaching total of over 90%.

Recording with PVR-250, 720x576, 7000/8000 bps.

Hardware: Celeron 1.3 GHz, 512 MB.

Hard disk DMA is on.

Fecora Core 2, Kernel 2.6.9, Myth 0.16.

I was once using a P-III/866 in another machine, that had no problems
with the same settings (resolution, bitrate), playing at 50% CPU total.

Any hints?

Thanks!

Thomas

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doug at ties

Jan 5, 2005, 11:09 AM

Post #2 of 13 (3844 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 with NVidia TV-out [In reply to]

Thomas Börkel wrote:
> HI!
>
> Using NVidia 6629 TV-out with XV for playback in mythfrontend, I get:
>
> - 1% CPU for mythfrontend
> - 40% CPU for X
>
> But total CPU is at 80%, causing prebuffering pause every now and then
> (and all the time, if I enable kernel deint in addition).
>
> Strange is, I can't see any other process with "top", that takes the
> rest of the CPU (the other 40%).

[snip]

> Fecora Core 2, Kernel 2.6.9, Myth 0.16.

Kernel 2.6.x has changed the way the /proc filesystem reports CPU time,
such that 'top' does not see CPU time consumed by process threads of the
original program.

See e.g. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=222817
(starting about halfway down) for some discussion; evidently 2.6.10
changes this behavior.

-Doug

Attachments:

signature.asc (0.25 KB)

thomas at boerkel

Jan 5, 2005, 1:42 PM

Post #3 of 13 (3839 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 with NVidia TV-out [In reply to]

I should also add, that I am using onboard sound of an MSI board, if
that matters.

But a 1.3 GHz Celery should handle MPEG2 with no problems, right?

Thomas Börkel wrote:
> HI!
>
> Using NVidia 6629 TV-out with XV for playback in mythfrontend, I get:
>
> - 1% CPU for mythfrontend
> - 40% CPU for X
>
> But total CPU is at 80%, causing prebuffering pause every now and then
> (and all the time, if I enable kernel deint in addition).
>
> Strange is, I can't see any other process with "top", that takes the
> rest of the CPU (the other 40%).
>
> Watching LiveTV without prebuffering pause is impossible, because that
> adds another 10% CPU, reaching total of over 90%.
>
> Recording with PVR-250, 720x576, 7000/8000 bps.
>
> Hardware: Celeron 1.3 GHz, 512 MB.
>
> Hard disk DMA is on.
>
> Fecora Core 2, Kernel 2.6.9, Myth 0.16.
>
> I was once using a P-III/866 in another machine, that had no problems
> with the same settings (resolution, bitrate), playing at 50% CPU total.
>
> Any hints?
>
> Thanks!
>
> Thomas
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

thomas at boerkel

Jan 5, 2005, 1:45 PM

Post #4 of 13 (3841 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 with NVidia TV-out [In reply to]

HI!

Doug Larrick wrote:

>> Fecora Core 2, Kernel 2.6.9, Myth 0.16.
>
>
> Kernel 2.6.x has changed the way the /proc filesystem reports CPU time,
> such that 'top' does not see CPU time consumed by process threads of the
> original program.
>
> See e.g. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=222817
> (starting about halfway down) for some discussion; evidently 2.6.10
> changes this behavior.

Thanks for this info! Is there another tool, that reports totals with 2.6.9?

Thomas

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doug at ties

Jan 5, 2005, 2:12 PM

Post #5 of 13 (3877 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 with NVidia TV-out [In reply to]

Thomas Börkel wrote:
> Thanks for this info! Is there another tool, that reports totals with
> 2.6.9?

Not that I know of.

-Doug

Attachments:

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freedenizen at gmail

Jan 5, 2005, 2:47 PM

Post #6 of 13 (3863 views)
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Re: Unexplainable high CPU while watching MPEG2 with NVidia TV-out [In reply to]

On Wed, 05 Jan 2005 17:12:52 -0500, Doug Larrick <doug [at] ties> wrote:
> Thomas Börkel wrote:
> > Thanks for this info! Is there another tool, that reports totals with
> > 2.6.9?
>
> Not that I know of.
>
> -Doug

Bah, I'm running 2.6.8.1-epia1 and I have this same problem. I was
hopefull that there would be a fix other then 2.6.10 as there isn't
even an epia1 patch for 2.6.9 yet.
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a.f.6 at pobox

Jan 5, 2005, 9:23 PM

Post #7 of 13 (3837 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 with NVidia TV-out [In reply to]

How about reducing the resolution? Unless you have HDTV, a normal TV
has only 525x525 resolution. Running at 640x480 will reduce the load
25%.

Do you have either glx or fb support for your video card?

On Wed, 2005-01-05 at 19:49 +0100, Thomas Börkel wrote:
> HI!
>
> Using NVidia 6629 TV-out with XV for playback in mythfrontend, I get:
>
> - 1% CPU for mythfrontend
> - 40% CPU for X
>
> But total CPU is at 80%, causing prebuffering pause every now and then
> (and all the time, if I enable kernel deint in addition).
>
> Strange is, I can't see any other process with "top", that takes the
> rest of the CPU (the other 40%).
>
> Watching LiveTV without prebuffering pause is impossible, because that
> adds another 10% CPU, reaching total of over 90%.
>
> Recording with PVR-250, 720x576, 7000/8000 bps.
>
> Hardware: Celeron 1.3 GHz, 512 MB.
>
> Hard disk DMA is on.
>
> Fecora Core 2, Kernel 2.6.9, Myth 0.16.
>
> I was once using a P-III/866 in another machine, that had no problems
> with the same settings (resolution, bitrate), playing at 50% CPU total.
>
> Any hints?
>
> Thanks!
>
> Thomas
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
--
Adam Felson <a.f.6 [at] pobox>

_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

thomas at boerkel

Jan 6, 2005, 1:17 AM

Post #8 of 13 (3833 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 with NVidia TV-out [In reply to]

HI!

Adam Felson wrote:
> How about reducing the resolution? Unless you have HDTV, a normal TV
> has only 525x525 resolution. Running at 640x480 will reduce the load
> 25%.

I can try that, but the thing is, another computer with P-III/866 had no
problems with the same resolution.

> Do you have either glx or fb support for your video card?

How can I tell?

Isn't it too much that X uses 40% CPU while playing on a Celeron 1.3
GHz? I think, X used only a few percent on my P-III/866 back then.

Thomas

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a.f.6 at pobox

Jan 6, 2005, 6:15 AM

Post #9 of 13 (3822 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 with NVidia TV-out [In reply to]

On Thu, 2005-01-06 at 10:17 +0100, Thomas Börkel wrote:
> HI!
>
> Adam Felson wrote:
> > How about reducing the resolution? Unless you have HDTV, a normal TV
> > has only 525x525 resolution. Running at 640x480 will reduce the load
> > 25%.
>
> I can try that, but the thing is, another computer with P-III/866 had no
> problems with the same resolution.
A PIII would definitely have to have some kind of hardware assist. I at
one point played around with a 500mhz pIII and was getting less than 10
frames/second before I got the fb working on the matrox g200 card I was
using.

>
> > Do you have either glx or fb support for your video card?
>
> How can I tell?
>
xdpyinfo

> Isn't it too much that X uses 40% CPU while playing on a Celeron 1.3
> GHz? I think, X used only a few percent on my P-III/866 back then.

yes. I think it's doing XV framebuffer scalling in software.

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thomas at boerkel

Jan 6, 2005, 8:26 AM

Post #10 of 13 (3856 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 with NVidia TV-out [In reply to]

HI!

Adam Felson wrote:
>>I can try that, but the thing is, another computer with P-III/866 had no
>>problems with the same resolution.
>
> A PIII would definitely have to have some kind of hardware assist. I at
> one point played around with a 500mhz pIII and was getting less than 10
> frames/second before I got the fb working on the matrox g200 card I was
> using.

Well, since it claims to use Xv (mytfrontend write that to the concole),
it should have hardware assist.

>>>Do you have either glx or fb support for your video card?
>>
>>How can I tell?
>
> xdpyinfo

Looks good. Please see output attached.

>>Isn't it too much that X uses 40% CPU while playing on a Celeron 1.3
>>GHz? I think, X used only a few percent on my P-III/866 back then.
>
> yes. I think it's doing XV framebuffer scalling in software.

But why?

Thomas

Attachments:

xdpyinfo.txt (11.6 KB)

joleu at web

Jan 6, 2005, 2:30 PM

Post #11 of 13 (3850 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 with NVidia TV-out [In reply to]

I had the same problem. I have got an old Nvidia TNT 1 with TV-Out. Now I use
the riva-framebuffer driver of the kernel and the builtin nv-driver of X11. I
added "Load "xv"" in my XF86Config-4. Now it works.

> HI!
>
> Using NVidia 6629 TV-out with XV for playback in mythfrontend, I get:
>
> - 1% CPU for mythfrontend
> - 40% CPU for X
>
> But total CPU is at 80%, causing prebuffering pause every now and then
> (and all the time, if I enable kernel deint in addition).
>
> Strange is, I can't see any other process with "top", that takes the
> rest of the CPU (the other 40%).
>
> Watching LiveTV without prebuffering pause is impossible, because that
> adds another 10% CPU, reaching total of over 90%.
>
> Recording with PVR-250, 720x576, 7000/8000 bps.
>
> Hardware: Celeron 1.3 GHz, 512 MB.
>
> Hard disk DMA is on.
>
> Fecora Core 2, Kernel 2.6.9, Myth 0.16.
>
> I was once using a P-III/866 in another machine, that had no problems
> with the same settings (resolution, bitrate), playing at 50% CPU total.
>
> Any hints?
>
> Thanks!
>
> Thomas
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

thomas at boerkel

Jan 7, 2005, 1:00 AM

Post #12 of 13 (3829 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 - SOLVED (partly) [In reply to]

HI!

Found the cause: AGP was disabled!

I am using the 2.6.9 FC2 kernel from atrpms and this kernel has AGPGART
enabeled.

I also had set "NvAGP" to "1" (= use NVidia-AGP) in xorg.conf, like in
my other Myth box and as recommended in Jarod's doc.

The result was, that the NVidia driver could not use NVidia-AGP, because
AGPGART was enabled in the kernel and so I had no AGP at all, resulting
in 40% CPU usage from X while playing.

Now I set "NvAGP" to "3", so that the NVidia driver is able to use
AGPGART and now X uses only 13% CPU.

I think, this could go down to 1% (as in my other Myth box), if I could
disable AGPGART in the kernel and use NVidia-AGP.

But how to disable AGPGART in that kernel? I tried agpgart=no as boot
parameter, but that did not help.

Thanks!

Thomas

Thomas Börkel wrote:
> HI!
>
> Using NVidia 6629 TV-out with XV for playback in mythfrontend, I get:
>
> - 1% CPU for mythfrontend
> - 40% CPU for X
>
> But total CPU is at 80%, causing prebuffering pause every now and then
> (and all the time, if I enable kernel deint in addition).
>
> Strange is, I can't see any other process with "top", that takes the
> rest of the CPU (the other 40%).
>
> Watching LiveTV without prebuffering pause is impossible, because that
> adds another 10% CPU, reaching total of over 90%.
>
> Recording with PVR-250, 720x576, 7000/8000 bps.
>
> Hardware: Celeron 1.3 GHz, 512 MB.
>
> Hard disk DMA is on.
>
> Fecora Core 2, Kernel 2.6.9, Myth 0.16.
>
> I was once using a P-III/866 in another machine, that had no problems
> with the same settings (resolution, bitrate), playing at 50% CPU total.
>
> Any hints?
>
> Thanks!
>
> Thomas
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

a.f.6 at pobox

Jan 7, 2005, 7:16 AM

Post #13 of 13 (3823 views)
Permalink

Re: Unexplainable high CPU while watching MPEG2 - SOLVED (partly) [In reply to]

that's weird. glx shouldn't have loaded.

On Fri, 2005-01-07 at 10:00 +0100, Thomas Börkel wrote:
> HI!
>
> Found the cause: AGP was disabled!
>
> I am using the 2.6.9 FC2 kernel from atrpms and this kernel has AGPGART
> enabeled.
>
> I also had set "NvAGP" to "1" (= use NVidia-AGP) in xorg.conf, like in
> my other Myth box and as recommended in Jarod's doc.
>
> The result was, that the NVidia driver could not use NVidia-AGP, because
> AGPGART was enabled in the kernel and so I had no AGP at all, resulting
> in 40% CPU usage from X while playing.
>
> Now I set "NvAGP" to "3", so that the NVidia driver is able to use
> AGPGART and now X uses only 13% CPU.
>
> I think, this could go down to 1% (as in my other Myth box), if I could
> disable AGPGART in the kernel and use NVidia-AGP.
>
> But how to disable AGPGART in that kernel? I tried agpgart=no as boot
> parameter, but that did not help.
>
> Thanks!
>
> Thomas
>
> Thomas Börkel wrote:
> > HI!
> >
> > Using NVidia 6629 TV-out with XV for playback in mythfrontend, I get:
> >
> > - 1% CPU for mythfrontend
> > - 40% CPU for X
> >
> > But total CPU is at 80%, causing prebuffering pause every now and then
> > (and all the time, if I enable kernel deint in addition).
> >
> > Strange is, I can't see any other process with "top", that takes the
> > rest of the CPU (the other 40%).
> >
> > Watching LiveTV without prebuffering pause is impossible, because that
> > adds another 10% CPU, reaching total of over 90%.
> >
> > Recording with PVR-250, 720x576, 7000/8000 bps.
> >
> > Hardware: Celeron 1.3 GHz, 512 MB.
> >
> > Hard disk DMA is on.
> >
> > Fecora Core 2, Kernel 2.6.9, Myth 0.16.
> >
> > I was once using a P-III/866 in another machine, that had no problems
> > with the same settings (resolution, bitrate), playing at 50% CPU total.
> >
> > Any hints?
> >
> > Thanks!
> >
> > Thomas
> >
> > _______________________________________________
> > mythtv-users mailing list
> > mythtv-users [at] mythtv
> > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
--
Adam Felson <a.f.6 [at] pobox>

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http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

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