[mythtv-users] diskless xBox stuttering - was Help Diskless frontend

[Ben Dash]

--- George Nassas wrote:
> On 5-Nov-05, at 10:20 PM, Ben Dash wrote:
> > since I changed to a 2.6 kernel I get no errors
> I'm running 2.4 because I read the 2.6 fatx driver
> isn't quite ready 
> for prime time. Do you do any updating of the xbox's
> filesystem while 
> you're in linux? 

No.  The only thing I'm using the native HDD for is
swap and that seems fine with the fatX drivers for
2.6.  I read somewhere that a major problem with FatX
for 2.6 was a lack of long filename support and swap
doesn't need that.

> > I just don't understand why I'm getting stuttering
> > when my CPU utilization is so low, i.e. 50%.  I
> had a
> 
> Could it be something to do with syncing updates to
> the vertical 
> retrace? I've never had those kinds of issues on any
> of my FEs but I 
> think some past threads on this list that mentioned
> that. One of those 
> things you skim and file away for future use. Look
> for Use OpenGL VSync 
> in the TV Playback menus.
> 
> BTW, does the frontend log say anything?

The frontend log just says "prebuffering pause".

I had an interesting development this weekend, I would
have replied to this thread earlier but my PC was in
pieces for an upgrade.  Anyway, my development was
that I found that if I run an xterm in the background
and run top on it, then I get hardly any "prebuffering
pause" stuttering.

The stuttering goes from once every 10 seconds,
without the xterm runing top, to once every 10 minutes
with the xterm running top.  Interestingly, when a
stutter occurs the CPU utilization appeared to go down
not up.  Clearly the CPU isn't the limiting factor in
this case.

I have a gigabit switch so I doubt that I have a
network bandwidth problem.  My myth backend server is
a different machine than my NFS root server (note that
the xBox frontend is diskless with an NFS root except
for a local fatX swap).

So, the current status is that I, and more importantly
my wife, can experience stutter free live TV and
recorded shows at 640x480, which is GREAT.  All I have
to do is start up an xterm running top in the
background.

This seems more than a little wierd though.

Does anyone have any idea why this solution is able to
mask the problem and, if so, what a real solution
could be?

Thanks!

Ben


		
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