Centralization of graphical awesomeness

Carsten Haitzler (The Rasterman) raster at rasterman.com
Mon Oct 26 12:51:24 CET 2009

On Mon, 26 Oct 2009 13:57:27 +0300 Evgeniy Karyakin <anthropophagite at gmail.com>

> 2009/10/26 Carsten Haitzler <raster at rasterman.com>:
> > you want speed? you will need to give up something. if you still want it to
> > look nice, then drop pixels. its the simplest and easiest solution. its the
> > right resolution for that cpu anyway. the glamo will still hurt you, but
> > not as much.
>    I'm sure everybody who has any professional connections with
> Freerunner+Glamo development already took all possible measures to
> solve this problem. But what concrete steps were taken to ease Glamo
> bottleneck? If its throughput is so narrow, can we lower amount of

none. it's a hardware issue. you simply cant read or write to video ram faster
than that. andy tried timing stuff all that happened was instability from
memory. glamo is most likely also the cause for the cpu runnig at 400 not
500mhz. the extra load on the memory bus (because glamo is hooked there
externally providing another addressable chip) probably caused the instability.
remove it and there is a big change the cpu could run at 500mhz instead of 400.
it's rated to do 500. (yes power consumption would go up - but it'd only be up
while its on. when suspended it wont matter).

> data flowing through it? There's one neighbor unanswered thread with a

render on the device - and this will then limit what you can render. evas can't
be fully accelerated by the glamo. it has too many opretations. a bit like
asking why quake4 is slow on a a voodoo2. it does much mroe than the old gfx
chip ever was designed to do and you will hit software fallbacks. evas has
multiple engnines. software (which is what is used - the 16bit renderer as
opposed to the full 32bit one). it has xrender - if xrender were fully
accelerated this should be better, but glamo cannot fully accelerate all the
ops evas uses, so... it will rely on software fallbacks. thus slow down. my bet
is you'll end up same speed as the pure software engine, or worse. aftera
bunch of hard work you'll have gone nowhere. evas also has a gl and gles2
engine - but thats no use on glamo. it's gles1.1 and very limited (from memory
texture size is 256x256 which is pretty useless for 2d as most data you deal
with breaks these bounds).

> question on how to start the kernel with qvga resolution. Aside of

no need to do that - just configure x for qgva. :)

> this, what can be reduced, for example amount of available colours
> (256 or even 16)? And if this [too] low throughput only of video
> memory channel?

256 won't help. it increases complexity and really reduces display quality
through the floor. the best best is qvga 16bpp. its simple. it doesn't require
any hard work. it is actually the most common resolution for most phones and
devices out there so the software is more portable if you work on that (and
then higher). but... in the past everyone has moaned and complained and refused
to use it, and insisted on their vga resolution... and then complained about

if people don't believe me that the gta02 is just plain a "bad bit of
hardware and you have few choices" here's some examples. here'es an ooold efl
demo app i did:

and here it is on a 206mhz ipaq 3660 with 64m ram and 16m flash, qvga(240x320).
it's from like 2001/2002 (from memory). its ancient. and watch it run evas:

here is something i videoed today. it's an samsung s3c6410 at 667 mhz, 128m
ram, and 800x480 (higher res than gta02):


everywhere i look... theres much better hardware. if you look at performance vs
age of hardware (when it was released) gta02 is almost at the bottom of the
pile. :( you simply have a bad piece of hardware if you want graphics
performance. as soon as you acknowledge that and either downgrade the device
resolution for example to bring it in line with its performance, or just use
different hardware, the better life will be :)

------------- Codito, ergo sum - "I code, therefore I am" --------------
The Rasterman (Carsten Haitzler)    raster at rasterman.com

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