x in om2007.2

[Carsten Haitzler (The Rasterman)]

On Sun, 27 Jul 2008 19:08:15 +0530 "sparky mat" <max at sparkymat.net> babbled:

> On Sun, Jul 27, 2008 at 5:33 PM, Marcus Bauer <marcus.bauer at gmail.com>wrote:
> 
> > On Sun, 2008-07-27 at 13:26 +0200, Michael 'Mickey' Lauer wrote:
> > > Am Sonntag 27 Juli 2008 09:52:57 schrieb sparky mat:
> > > > kinda new here. i noticed that om2007.2 and asu are slower than qtopia
> > > > (the one from trolltech, not the x11 port). i presume its partly
> > > > because X is being used.
> > >
> > > It's less a problem of X and more a problem of Gtk+ taking ages to
> > (re)draw
> > > things on the screen.
> >
> > It is well known that you don't like GTK+ - fine. But just stop
> > spreading your FUD against GTK+:
> >
> >        a) GTK is quite snappy on the neo1973 (GTA01) thus the problem
> >        is not GTK but the limited memory bandwith on the
> >        Freerunner/GTA02 due to the glamo chip.
> >
> 
> Why is this so (lesser memory bandwidth due to the glamo chip)?

because that is the nature of the hardware on the freerunner. the glamo
throttles write rates to its video ram (or read rates) and thus brings the
system into wait states waiting on the glamo (basically lock in your cpu down to
doing nothing WHILE you try and write data, and the writes do not go as fast
asht e cpu can manage - they hit about 7mb/sec - thats a fair bit less than
your average 100mbit ethernet can transport, and thats the video memory
access from the cpu). it's just that is how it is, and it is a limit you have to
code around - read/write less data to/from video ram on updates.

>        b) the neod eats up to 60% CPU on the Freerunner (GTA02) because
> >        it opens all /dev/input/event* and thus it opens the
> >        accelerometers and get 200 interrupts per second - for
> >        absolutely nothing.
> >
> >        But it massively slows down OM2007.2.
> >
> 
> I am assuming neod is the "event" handler. So does it do polling or waiting
> for events? (Ok, I guess I should prolly start looking at the code :-) )
> 
> And unless I am mistaken, isnt this a whole another thread in the mailing
> list? I mean, high cpu-usage of neod?
> 


-- 
Carsten Haitzler (The Rasterman) <raster at openmoko.org>