[Tremor] Tremor performace on ARM

[Daniel Kahn Gillmor]

On Thu 2007-11-15 12:50:23 -0500, Vamsi Mohan Reddy Pulagam wrote:

> By MIPS I mean the minimum speed at which the ARM processor should
> be run to have a successfull, glitch free, real time vorbis
> playback.

It seems to me like that would depend on both the bitrate of the
stream itself, and what other activity the device is expected to
sustain in the meantime.

I can give you one datapoint: my NSLU2 (266MHz) running debian etch
seems to consume about 50% of its CPU when playing back a stream
like this:

0 dkg at squeak:~$ ogginfo foo.ogg
Processing file "foo.ogg"...
New logical stream (#1, serial: 7cc3c7ee): type vorbis
Vorbis headers parsed for stream 1, information follows...
Version: 0
Vendor: Xiph.Org libVorbis I 20040629 (1.1.0 rc1)
Channels: 2
Rate: 44100

Nominal bitrate: 192.000000 kb/s
Upper bitrate not set
Lower bitrate not set
Vorbis stream 1:
	Total data length: 5601177 bytes
	Playback length: 4m:03.893s
	Average bitrate: 183.725465 kb/s
Logical stream 1 ended
0 dkg at squeak:~$ 

Here's a baseline read:

0 dkg at igor:~$ egrep '^(Processor|BogoMIPS)' /proc/cpuinfo 
Processor	: XScale-IXP42x Family rev 1 (v5l)
BogoMIPS	: 266.24
0 dkg at igor:~$ vmstat 1 5 
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 3  0    708   1448    964  10052    0    0     0     0    2    6  3  0 96  0
 2  0    708   1444    964  10052    0    0     0     0  104  307  1  0 99  0
 2  0    708   1444    964  10052    0    0     0     0  103  306  0  0 100  0
 2  0    708   1444    964  10052    0    0     0     0  103  306  0  0 100  0
 2  0    708   1444    964  10052    0    0     0     0  103  306  0  0 100  0
0 dkg at igor:~$ 

Then i set my installation of mpd (built with tremor) playing that
stream, and after a brief spike of 100% CPU (buffering, maybe?), it
stabilizes to this:

0 dkg at igor:~$ vmstat 1 5
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 0  0    708   1288    992  10052    0    0     0     0    2    6  3  0 96  0
 1  0    708   1284    992  10052    0    0     0     0  371  165 47  5 49  0
 1  0    708   1284    992  10052    0    0     0     0  372  163 44  7 49  0
 1  0    708   1284    992  10052    0    0     0     0  366  155 47  4 49  0
 1  0    708   1284    992  10052    0    0     0     0  367  168 44  5 51  0
0 dkg at igor:~$ 

hth,

        --dkg

PS Please don't CC me.  I read the list.  Thanks!
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