[vlc] Re: Kernel-2.6.0-test

[Jean-Paul Saman]

Manu Abraham wrote:
> Hi,
>          Does anybody know why i get a chequered video on a Set top box
> under kernel 2.4.20 RH9 on the machine where i run vlc, but not if i run
> kernel-2.6.0-test6 ?

In 2.6.0-test6 the io scheduler used is by default the anticipatory 
scheduler known as aa. Others are: deadline, cfq and noop.

The io scheduling policy determines based on policies which disk 
requests gets served when. The deadline, aa and cfq policies try to make 
sure that no disk request is waiting too long. This results in much 
better streaming performance then on the previous kernel series. If a 
disk request is waiting too long then you can get io starvation for a 
request.  Which in turn results in "chequered" video as you call it.

In 2.4.20 this mechanisme does not exist and thus all disk requests 
under are not optimized with streaming video/audio in mind but for the 
common case (known as best-effort).

-- 
Kind greetings,

Jean-Paul Saman



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