[linux-audio-dev] Re: Measuring latency on my Apple G3

[Michel Dänzer]

On Mon, 2003-07-21 at 13:46, Ismael Valladolid Torres wrote: 
> Michel Dänzer escribio el 21/07/03 13:09:
> > First of all, you mentioned in another post that you use x11perf to
> > create X11 stress. Are there also problems with real world apps?
> 
> "Real world" apps work properly (except for the Gnome theme manager 
> which displays garbage). 

Probably a GTK bug, not related to this thread. The point is real world
as opposed to synthetic throughput benchmarks like x11perf.

> I only find video performance using Linux a lot lower than using 
> any of the Mac OS's.

Which isn't very surprising, as they can use parts of the graphics chip
that we don't have specs for, for one.


> > Also keep in mind that neither the vanilla 2.4 kernel nor the X server
> > were designed for low latency. Have you tried the low latency and/or
> > O(1) scheduler kernel patches, and not running the X server with
> > negative nice values if you are?
> 
> Both of those patches (A. Morton and R. Love's ones) were applied to my 
> kernel. 

Beware that at least the low latency patch needs fiddling with
arch/ppc/config.in to actually be enabled (check with grep LOLAT
.config), and that the preempt patch (which I assume you mean by R.
Love's) actually made things worse for me when I tried it on PPC a while
ago. This may have been fixed in the meantime though.

> I don't know about running the X server with different nice values, 

sudo dpkg-reconfigure xserver-common

> which advantage would I get?

The X server might take less CPU away from other processes. Or maybe the
problem is the other way around. :) YMMV.


-- 
Earthling Michel Dänzer   \  Debian (powerpc), XFree86 and DRI developer
Software libre enthusiast  \     http://svcs.affero.net/rm.php?r=daenzer