why openmoko is so slow? Is it a joke?

Al Johnson openmoko at mazikeen.demon.co.uk
Mon Jul 13 16:36:24 CEST 2009

On Monday 13 July 2009, mobi phil wrote:
> Hello all
> I spent this weekend some time to compare and to try to understand what is
> slow, why is openmoko slow... At least concerning the display I came to the
> concusion that X windows is/should not too much to blame.
> I installed the latest SHR distro on a mSD card, and run it both on
> Freerunner and ETEN glofiish M800, thanks to the gnufiish project. I have
> to say that everything on eten m800 is much faster, rendering, screen
> refresh, scrolling etc. However both devices have the same processor at the
> sam speed, andsame SD card. I run both x11perf, and a little program to
> draw rectangles on the framebuffer. The speed ratio between the openmoko
> and eten m800 framebuffer is 7/10, this measured with my small tool. I run
> "x11perf -all" on the ETEN M800 with the Xfbdev, you will find the results
> attached. I tried to run x11pref -all on freerunner with Xfbdev but it
> crashes at the beginning of the second test... I will try to run the same
> here the comparison of the first test (Dot)
> for gnufiish
>   6000000 reps @   0.0009 msec (1120000.0/sec): Dot
>   6000000 reps @   0.0009 msec (1130000.0/sec): Dot
>   6000000 reps @   0.0009 msec (1120000.0/sec): Dot
>   6000000 reps @   0.0009 msec (1120000.0/sec): Dot
>   6000000 reps @   0.0009 msec (1130000.0/sec): Dot
>   30000000 trep @   0.0009 msec (1120000.0/sec): Dot
> for freerunner..
>   2000000 reps @   0.0025 msec (394000.0/sec): Dot
>   2000000 reps @   0.0025 msec (402000.0/sec): Dot
>   2000000 reps @   0.0025 msec (393000.0/sec): Dot
>   2000000 reps @   0.0028 msec (360000.0/sec): Dot
>   2000000 reps @   0.0026 msec (391000.0/sec): Dot
>   10000000 trep @   0.0026 msec (388000.0/sec): Dot
> so, you can see the differences between the numbers... However I am a bit
> confused, and need to read once more the manpage to know exactly how to
> interpret the numbers, but at first glance, there is a huge difference...
> As I said, I wil try to run the x11perf on the Xglamo to see if there are
> any improvement... However I am not sure that the acceleration would solve
> the problem... I think that the bottleneck is the data bus, or? the story
> with the SDcard connected to the glamo chip...

The bus bottleneck between CPU and Glamo has been discussed extensively in the 
past, complete with theoretical and measured bandwidth, and its implications 
on maximum framerate. This makes the graphics on the 400MHz FR slower than the 
266MHz 1973. If the 500MHz M800 has a similar screen connection to the 1973, 
and the drawing speed scales with CPU speed, you would expect roughly the 
performance difference you are seeing. This shouldn't be a surprise.

> So... my question is ... is it a joke that the openmoko framebuffer is so
> slow compared to other similar phones???

That depends on your sense of humour ;-) 

> In this case I would really advice
> people to refrain in buying the openmoko, and better go for glofiish M800,
> that has a keyboard and radio as plus, and kernel support is almost
> ready... Again, on M800 SHR is really fluid... However loading applications
> is slow... Maybe libraries are not cached well?
> rgrds,
> mobi phil
> being mobile, but including technology
> http://mobiphil.com

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