Re: [hatari-devel] OS X performance problem

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi,

On torstai 05 kesäkuu 2014, Nicolas Pomarède wrote:
> Fact is that if you use fastforward, all parts of the code will be
> called several times more per VBL. So, instead of doing 50 refresh per
> second, you might do 200 per sec for example (depend on your CPU's
> speed).

Hm, if (host) Vsync happens only with OSX, Hatari can run faster
on Linux.  Because on OSX one could get only 60 FPS, --frameskips
value would directly dictate how much faster emulation can run.

This is easy to test, just increase --frameskips to a value where
you don't get anymore faster speed (or until "top" shows Hatari
to use CPU fully).

On my machine, I can get Frantick startup time (with frantek module
loading and Hatari statusbar) to ~4 secs.


> This means x4 more calls to refresh the status bar ; so if SDL's
> implementation on OSX is the bottleneck, you loose more cpu by
> fastforwarding and doing more screen refreshes than the SDL backend can
> accept.
> 
> In the end, what you gained in emulation speed by running cpu/video/...
> at x4 is lost by the OS calls needed to refresh screen in SDL.


	- Eero