[clug] raspberry pi MythTV frontend or another option?

Stephen Gibson Stephen.Gibson at anu.edu.au
Sun Mar 24 23:16:17 MDT 2013


At $42 (Element 14, throw in a case for $8 and get free delivery) the 
Rpi is too much fun to be without one.

The 512Mb model is more robust that the old 256Mb model, and has some 
power supply/USB faults fixed.

A camera module (~$25) is about to be released.

It runs the latest kernels 3.6.x (raspbian+rpi-update).

1GHz overclock (on demand) reveals a "real world" performance (=my 
numerical code) about a factor of 1/10 slower than my Macbook (1,1) 2GHz 
(see below). However, in general the Rpi "feels" responsive.

The broadcom chip has a GPU and so, in principle, can handle graphics 
well (with the codec).

I normally run mine headless.  I have tried, without success, 
raspbmc+mythbox front end to a mythtv backend. However, this is probably 
due to my lack of persistence, wifi connection (in bed room), and a too 
recent mythtv backend.  Just BTW an ATV2+xbmc+mythbox provides a nice 
interface, but also, refuses to play the actual recordings.

For the Rpi there is additional bonus fun in getting peripherals to 
work, such as a kindle 4 screen.

Steve.

Old benchmark 20/9/12  (I can't recall whether this is the 256Mb or 
512Mb Rpi):

Rpi with ondemand 1GHz overclock

[raspberrypi:~]$ sudo /opt/vc/bin/vcgencmd measure_temp
temp=49.8'C
[raspberrypi:~]$ cat /sys/class/thermal/thermal_zone0/temp
49768
[raspberrypi:~]$ sudo /opt/vc/bin/vcgencmd measure_clock arm
frequency(45)=1000000000
[raspberrypi:~]$ cat /sys/class/thermal/thermal_zone0/temp
54610
[raspberrypi:~]$ sudo /opt/vc/bin/vcgencmd measure_temp
temp=55.7'C

[raspberrypi:.+ench-byte-2.2.3]$ ./nbench

BYTEmark* Native Mode Benchmark ver. 2 (10/95)
Index-split by Andrew D. Balsa (11/97)
Linux/Unix* port by Uwe F. Mayer (12/96,11/97)

TEST                : Iterations/sec.  : Old Index   : New Index
                     :                  : Pentium 90* : AMD K6/233*
--------------------:------------------:-------------:------------
NUMERIC SORT        :           318.8  :       8.18 : 2.69
STRING SORT         :          44.107  :      19.71 : 3.05
BITFIELD            :       1.198e+08  :      20.55 : 4.29
FP EMULATION        :          59.928  :      28.76 : 6.64
FOURIER             :          3026.9  :       3.44 : 1.93
ASSIGNMENT          :          4.1601  :      15.83 : 4.11
IDEA                :          1001.6  :      15.32 : 4.55
HUFFMAN             :          620.54  :      17.21 : 5.49
NEURAL NET          :          4.7657  :       7.66 : 3.22
LU DECOMPOSITION    :          127.17  :       6.59 : 4.76
==========================ORIGINAL BYTEMARK
RESULTS==========================
INTEGER INDEX       : 16.922
FLOATING-POINT INDEX: 5.579
Baseline (MSDOS*)   : Pentium* 90, 256 KB L2-cache, Watcom* compiler 10.0
==============================LINUX DATA
BELOW===============================
CPU                 :
L2 Cache            :
OS                  : Linux 3.2.27+
C compiler          : gcc version 4.6.3 (Debian 4.6.3-8+rpi1)
libc                : libc-2.13.so
MEMORY INDEX        : 3.774
INTEGER INDEX       : 4.594
FLOATING-POINT INDEX: 3.094
Baseline (LINUX)    : AMD K6/233*, 512 KB L2-cache, gcc 2.7.2.3, 
libc-5.4.38.

[raspberrypi:~]$ !time
time echo "scale=2000;4*a(1)" | bc -l
3.141592653589793238462643383279502884197169399375105820974944592307\
    <snip>

real    0m16.783s
user    0m16.460s
sys    0m0.010s

Real code:
/usr/bin/time -v ./cse -file cse.time > /dev/null &

     User time (seconds): 31.99
     System time (seconds): 2.29
     Percent of CPU this job got: 97%
     Elapsed (wall clock) time (h:mm:ss or m:ss): 0:35.14
     Average shared text size (kbytes): 0
     Average unshared data size (kbytes): 0
     Average stack size (kbytes): 0
     Average total size (kbytes): 0
     Maximum resident set size (kbytes): 1580
     Average resident set size (kbytes): 0
     Major (requiring I/O) page faults: 1
     Minor (reclaiming a frame) page faults: 6402
     Voluntary context switches: 52
     Involuntary context switches: 2406
     Swaps: 0
     File system inputs: 128
     File system outputs: 528
     Socket messages sent: 0
     Socket messages received: 0
     Signals delivered: 0
     Page size (bytes): 4096
     Exit status: 0




cf my Macbook (1,1)
2.0GHz---------------------------------------------------

!time
real    0m5.508s
user    0m5.304s
sys    0m0.000s

and
[Steve:.+ench-byte-2.2.3]$ ./nbench

BYTEmark* Native Mode Benchmark ver. 2 (10/95)
Index-split by Andrew D. Balsa (11/97)
Linux/Unix* port by Uwe F. Mayer (12/96,11/97)

TEST                : Iterations/sec.  : Old Index   : New Index
                     :                  : Pentium 90* : AMD K6/233*
--------------------:------------------:-------------:------------
NUMERIC SORT        :          938.04  :      24.06 :       7.90
STRING SORT         :            81.6  :      36.46 :       5.64
BITFIELD            :       3.627e+08  :      62.22  : 13.00
FP EMULATION        :          153.68  :      73.74  : 17.02
FOURIER             :           22072  :      25.10  : 14.10
ASSIGNMENT          :           24.97  :      95.02  : 24.64
IDEA                :          3490.2  :      53.38  : 15.85
HUFFMAN             :          1886.9  :      52.32  : 16.71
NEURAL NET          :          32.203  :      51.73  : 21.76
LU DECOMPOSITION    :          1049.5  :      54.37  : 39.26
==========================ORIGINAL BYTEMARK
RESULTS==========================
INTEGER INDEX       : 52.284
FLOATING-POINT INDEX: 41.330
Baseline (MSDOS*)   : Pentium* 90, 256 KB L2-cache, Watcom* compiler 10.0
==============================LINUX DATA
BELOW===============================
CPU                 : Dual GenuineIntel Genuine Intel(R) CPU
T2500  @ 2.00GHz 2000MHz
L2 Cache            : 2048 KB
OS                  : Linux 3.2.0-30-generic-pae
C compiler          : gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5)
libc                : libc-2.15.so
MEMORY INDEX        : 12.181
INTEGER INDEX       : 13.736
FLOATING-POINT INDEX: 22.923
Baseline (LINUX)    : AMD K6/233*, 512 KB L2-cache, gcc 2.7.2.3, libc-5.4.38



Real code:
  /usr/bin/time -v ./cse -file cse.time > /dev/null &
     User time (seconds): 3.66
     System time (seconds): 0.09
     Percent of CPU this job got: 90%
     Elapsed (wall clock) time (h:mm:ss or m:ss): 0:04.14
     Average shared text size (kbytes): 0
     Average unshared data size (kbytes): 0
     Average stack size (kbytes): 0
     Average total size (kbytes): 0
     Maximum resident set size (kbytes): 6128
     Average resident set size (kbytes): 0
     Major (requiring I/O) page faults: 8
     Minor (reclaiming a frame) page faults: 6479
     Voluntary context switches: 81
     Involuntary context switches: 422
     Swaps: 0
     File system inputs: 2072
     File system outputs: 528
     Socket messages sent: 0
     Socket messages received: 0
     Signals delivered: 0
     Page size (bytes): 4096
     Exit status: 0





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