Pandora, Some Actual Performance Numbers ..

Quote from ITT
Benchmarking Quake 2 on N8x0:
Running 'maqii +set basedir /media/mmc2/quetoo +set timedemo 1 +set vid_width 320 +set vid_height 240 +map demo2.dm2' gives me '618 frames, 35.5 seconds: 17.4 fps' and with '+set vid_width 400 +set vid_height 240' that matches the aspect on the n8x0 screen, and is default in my launcher gives '618 frames, 40.6 seconds: 15.2 fps'. I do think the zaurus has a bit better cpu, though I don't really know. I couldn't find any very good info on either zaurus or a q2 port for it either. Any optimzations that might have could probably benefit this too, so any info on this would be nice.
Laurent said:
Has someone tried to use an ARM compiler for nBench, yet?

Are you ready to pay several thousand dollars for a compiler? :p
Not necessary :)
It COULD be that some HAS the compiler at work.
A friend of mine bought a license for some month because he had to test ARM code for an university project.
Bad thing is, this was a year ago or something. But it COULD be that someone here as a similiar oppurtunity.

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I've read on IRC log, that TI has got an own NEON compiler that should be even better than the ARM one. So far I haven't read someone trying it out. I've read this also:
[10:17:45] <mru> transferring a 32-bit value from neon to an arm register takes something like 20 cycles
[10:18:14] <mru> the arm and neon pipelines are not tightly coupled

<mru> arm to neon register transfer is fast
[14:03:48] <mru> neon to arm is slow
[14:04:01] <torus> good to know..
[14:04:42] <mru> remember there's 16-entry instruction fifo between arm and neon
[14:05:18] <mru> so if you have some arm code to run, clever interleaving with neon instructions lets both execute at the same time
[14:18:03] <mru> to get maximum performance from neon, you need to use the full register width
[14:18:10] <mru> and avoid neon to arm register transfers
As a side note, NEON is likely to lock up the CPU when you overclock(core voltage dependent).
mru suggests RVDS 4.0 but he says, that it's not fully GCC compatible and has bugs, too. There is a 30 day trial available if you register.
[19:46:55] <geist> and we have full -mcpu=cortex-a8 + neon turned on
[19:47:07] <mru> which version?
[19:47:14] <geist> 2007q3 mostly
[19:47:27] <mru> that doesn't use neon at all
[19:47:30] <mru> only vfp
[19:53:19] <mru> expect 10-15% faster code from armcc
A more off topic note: Cortex A9 will have a pipelined VFP unit.