Re: Any way to do time keeping during kernel uncompression[ARM architecture]

[Dave Hylands <dhylands@xxxxxxxxx>]

Hi Sandeep


On Wed, Jan 30, 2013 at 6:35 PM, sandeep kumar <coolsandyforyou@xxxxxxxxx> wrote:
>
> Hi Dave.
> Ok
> Can you tell me which thing runs faster ?
> 1)Copy zImage(compressed kernel) from flash to Ram, jump to start, Relocate compress kernel, uncompress it...
> 2)Copy Image(uncompressed one) from flash to RAM and run it right away...
>
> My gut feeling says second one is better, thats what i m trying to prove here... :)

It depends on numerous factors:

1 - Your flash speed

2 - Your RAM speed

3 - Your CPU speed

4 - Whether you have code and/or data caches enabled

If you enable the caches, use DMA from NAND (so make your NAND as fast as possible), then option 1 usually blows away option 2, but your mileage may vary.

Dave Hylands

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@xxxxxxxxxxxxxxxxx
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies