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Old 03-18-2011, 07:40 PM   #1
santinelli.paolo
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speed problem after kernel updating on PXA270 platform


Hi,

I have ported/adapted the linux kernel 2.6.37 on my PXA270-based camera platform. Now a simple speed test program takes double time than with the previous kernel version (2.6.9). The cpu speed is the same for both kernels, 510 Mhz

The test program simply measures the time required to fill 1 MB of RAM with a constant value.

I didn't change the bootloader configuration, so the memory controller setting didn't change.

Any idea regarding the cause of this speed lack?

Does exist a way to test the cache memory functionality ?

Thanks

Paolo
 
Old 03-24-2011, 02:17 PM   #2
nini09
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The kernel can change memory configuration. That means that maybe memory configuration is changed on new kernel, 2.6.37.
 
Old 03-25-2011, 12:05 AM   #3
santinelli.paolo
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Hi nini09,

could be that the kernel changes the memory configuration. Do you have any idea where, in which file, could be the source code that manages that ?

Thanks

Paolo
 
Old 03-25-2011, 02:59 PM   #4
nini09
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Following link tell you Linux kernel startup.
http://en.wikipedia.org/wiki/Linux_startup_process.
Normally, boot loader doesn't use MMU but kernel is yes.
 
Old 03-26-2011, 10:48 AM   #5
santinelli.paolo
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Hi nini09,

thank you very much for the information. I will continue to work on this problem!

Paolo
 
  


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