[XviD-devel] Limit of 4 threads in the VfW GUI

[Radek Czyz]

If memory serves me right, the main reason why I was afraid of too many 
threads was because there was a silly hack in threading code: temporary 
memory used for qpel (and chroma?) interpolation, needed by rdo, is 
jammed in unused parts of frame memory. Too many threads with too small 
frame and it will just crash.

It's one of those things I always wanted to fix. With modern processors 
having four hyperthreaded cores, this might be worth fixing, as this 
code used to work nicely with hyperthreading in P4 days (and I haven't 
seen a benchmark since).

Radek

On 29/11/2010 2:25 AM, Marcin Jaworski wrote:
> Greetings.
>
> The VfW GUI limits the number of threads to 4
> (xvidcore/vfw/src/config.c, line 1478), but the core library has no such
> limitation. I know that the vertical resolution of the input effectively
> limits the number of threads that can be used, but is there a reason for
> hardcoding the limit in VfW to just 4? SysKin once warned about using
> "way too many" threads. Can>4 be too many for the algorithm to handle
> (can it cause crashes etc.)?
>
> Best regards,
> Marcin Jaworski
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