[mythtv] [PATCH] O_STREAMING patch

[Brian Foddy]

On Mon, 22 Dec 2003, Isaac Richards wrote:

> On Monday 22 December 2003 01:07 pm, steve at nexusuk.org wrote:
> > This patch sets the O_STREAMING flag when the ring buffer is opened to
> > instruct the kernel not to cache the data once it's been accessed.  The
> > result is a much more responsive frontend after watching TV since most of
> > the frontend's files haven't been expired from the kernel's pagecache.
> >
> > You also need the O_STREAMING kernel patch:
> >     http://kerneltrap.org/node/view/460
> 
> I dunno, defining the O_STREAMING in the source seems rather dangerous to me.  
> Potential clashes with things other than linux, etc..  Can't check for it 
> with an ifdef?
> 

According to the link, the patch is for 2.4.20-pre9, has it been tested
with newer kernels?  ie:  2.4.22+ 

I'm all in favor of the concept however.

They also mention of an improvement
possible in 2.5, anyone know if this was made in the 2.6 ?  There are some
other improvements in 2.6 that sound interesting for Mythtv:

Improved hyperthreading support.

Preempt kernel task for higher priority tasks.

Alsa and V4L2 included (already included in Mandrake).

There is a new system call (forget the name) that is optimized 
for reading data from HD and sending over network which might be
helpful to the backend.

Drawback:  Nvidia drivers may not work.

I might try an experiment on it in the coming weeks.
Brian