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

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

> Yes, but that solution is complicated as well and it would be a
> wasted effort after implementing O_DIRECT. And O_DIRECT gives
> us 300% of the usefulness:
>
> *  O_DIRECT solves the "Recordings menu sluggish" problem in an
>     elegant way.
>
> *  It makes all of VDR I/O on nnn.vdr files faster, as the kernel
>     can DMA directly between the device and the VDR buffer.
>
> *  It increases the performance of the entire system, by eliminating
>     the overhead of moving gigabytes of data in and out of the cache
>     needlessly and by keeping the cache memory available for useful data.
>

It's really ironic - first the caching was invented to keep over all system 
performance up, and now - it is contra productive for some cases...

I'am not an expert in caching, but i would look for an option, to set the 
maximum-cache size on a per file base. I mean, that files larger than XXX are 
not even tried to be hold completly in memory, but just the next XXX bytes. 
Maybe there is already such an option in the Linux caching scheme....


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