[vdr] Re: Recordings menu sluggish - *the* solution.

[Guido Fiala <gfiala@s.netic.de>]

On Sunday, 5. October 2003 14:34, Andreas Trauer wrote:
> So I think a kind of I/O subsystem must be implemented that suites our
> needs, i.e.
> Playback:
> - random access to every octet in the stream translating it to the
> required buffer(s),
> - a limited cache of a few minutes or less (sometimes you skip back to
> replay a szene, e.g. when a phone call interrupts you, or you want to
> enjoy the last goal of your favorite soccer team in slow motion ;-)).
> - a "big" readahead buffer that minimizes the read accesses while

Well - that would mean some more ioctl's that need to be called for special 
buffering - one has to tell the system what the stream is expected to behave 
to optimize caching strategy. As those could be called on the fly, the 
caching strategy could also be changed while the file is open.

Another idea would be a subsystem that "guesses" the right behaviour from 
statistical data...

All in all it would require data to be stored on a per file base used for 
read/write-caching.

> fetching "new" data
> Record:
> - a minimum write-section size. Probably we would need a bigger ring
> buffer for this (?)
>

The write buffering can be configured via 

/proc/sys/vm/bdflush

(that is while you probably see your hdd blink every 5 seconds for a short 
time - thats standard interval).

Is'nt there something similar for read?


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