15 computer science collegians looking for a project

[Martin Dengler]

On Fri, May 02, 2008 at 01:35:21AM +0200, Reinier Heeres wrote:
> Hi,
> 
> The problem you encountered was apparently caused by the compiler 
> warning.

Thanks -- that was it!

> Renaming all instances of 'round' with something else resulted 
> in the following here (also a C2):
> 
> [olpc at xo-0C-EC-18 ~]$ ./calibrator 431 4M callog
> 
> Calibrator v0.9e
> (by Stefan.Manegold at cwi.nl, http://www.cwi.nl/~manegold/)
> b790c008 -1215250424 4096 -4088
> b790cfff -1215246337 4096    -1
> b790d000 -1215246336 4096     0
> 
> MINTIME = 10000
> 
> analyzing cache throughput...
>       range      stride       spots     brutto-  netto-time
>     5242880           4     1310720       12472        3118
> 
> analyzing cache latency...
>       range      stride       spots     brutto-  netto-time
>     5242880           4     1310720      195660       97830
> 
> analyzing TLB latency...
>       range      stride       spots     brutto-  netto-time
>     1081344        1056        1024       10858        5429
> 
> 
> CPU loop + L1 access:      19.81 ns =   9 cy
>              ( delay:     959.51 ns = 414 cy )
> 
> caches:
> level  size    linesize   miss-latency        replace-time
>   1     64 KB   32 bytes   22.75 ns =  10 cy   23.15 ns =  10 cy
>   2    192 KB   32 bytes   64.73 ns =  28 cy   76.50 ns =  33 cy
> 
> TLBs:
> level #entries  pagesize  miss-latency
>   1       80       4 KB   126.25 ns =  54 cy

I wonder why I got different results...

bash-3.2$ echo `cat /ofw/ec-name`
PQ2D13
bash-3.2$ echo `cat /ofw/model`
C2
bash-3.2$ echo `cat /boot/olpc_build`
joyride 1897
bash-3.2$ uname -r
2.6.22-20080408.1.olpc.de2a86ff3b60edc
bash-3.2$ gcc --version
gcc (GCC) 4.1.2 20070925 (Red Hat 4.1.2-27)
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There
is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.

bash-3.2$ gcc calibrator.c -o calibrator -lm
bash-3.2$ ./calibrator 431 4M calibrator_OLPC_C2

Calibrator v0.9e
(by Stefan.Manegold at cwi.nl, http://www.cwi.nl/~manegold/)
b7866008 -1215930360 4096 -4088
b7866fff -1215926273 4096    -1
b7867000 -1215926272 4096     0

MINTIME = 10000

analyzing cache throughput...
      range      stride       spots     brutto-  netto-time
    5242880           4     1310720       12548        3137

analyzing cache latency...
      range      stride       spots     brutto-  netto-time
    5242880           4     1310720      197190       98595

analyzing TLB latency...
      range      stride       spots     brutto-  netto-time
    4325376        1056        4096       16122        8061


CPU loop + L1 access:      19.92 ns =   9 cy
             ( delay:     974.45 ns = 420 cy )

caches:
level  size    linesize   miss-latency        replace-time
  1    192 KB   32 bytes   79.23 ns =  34 cy  100.80 ns =  43 cy

TLBs:
level #entries  pagesize  miss-latency
  1      256       1 KB    31.72 ns =  14 cy

bash-3.2$


> Cheers,
> Reinier

Martin
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