[linux-audio-user] [ANN] jack_oscrolloscope 0.1

Dominic Sacré dominic.sacre at gmx.de
Tue Nov 21 18:37:16 EST 2006


On Tuesday 21 November 2006 21:42, Fons Adriaensen wrote:
> > I assume you're using SDL. If you can, try OpenGL, that should take
> > most of the work off the CPU.
>
> Rather the opposite, see below.
>
> > Another thing you could try is to change both occurences of
> > SDL_HWSURFACE in video.h to SDL_SWSURFACE. Does it make any
> > difference? On my machine it doesn't, so I wasn't sure what to use.
>
> It does help a bit, but not with -g:
>        |           -g
>     ---------------------
>     HW |   33%     94%
>     SW |   22%     93%

Well, this flag is not used in GL mode, so it's no surprise that it has no 
effect there. But it looks like I should be using software surfaces in 
SDL mode.

Do you have hardware accelerated OpenGL at all? Software emulated GL can 
be dog slow (much slower than SDL), that's the main reason why I added 
SDL support in the first place.
For comparison, on my machine, with 12 tracks, fullscreen 1280x960, I'm 
getting about 30% CPU load using OpenGL. That's with an Athlon XP 3000+ 
and a cheap, 4 year old, passively cooled Nvidia card.

> I've got an almost identical app
> (Yass - not yet released). With 100 updates per second, 32 channels,
> and the maximum scrolling speed it takes less than 1% of available CPU.
> So it's definitely not X11 taking all the time.

Wow, 1%?! Is that using plain X11? Sounds almost too good to be true.
I think it goes without saying that I'd be interested in seeing your 
code ;)

    Dominic



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