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

[Abu Rasheda]

On Wed, Feb 6, 2013 at 3:53 AM, sandeep kumar <coolsandyforyou at gmail.com>wrote:

> Dear All
> FYI:
> I got the below data in my board...
> For Zimage:
> Copy from eMMC to RAM(bootloader) & other stuff in bootloader -- 200msec
> Kernel relocation --- 1msec
> Kernel uncompression -- 700msec
> Total time taken --- 900msec approx
>
> For Image:
> Copy from eMMC to RAM(bootloader) & other stuff in bootloader -- 1400msec
>
> So in case of Uncompressed kernel image.. even though it doesnt need
> kernel uncompression, it is taking 500msec more in bootloader.
>
>
> Thanks
> Sandeep
>

How did you measure these times ?

On Thu, Jan 31, 2013 at 12:46 PM, Dave Hylands <dhylands at gmail.com> wrote:
>
>> Hi Sandeep
>>
>>
>>
>> On Wed, Jan 30, 2013 at 6:35 PM, sandeep kumar <coolsandyforyou at gmail.com>
>> 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
>>
>
>
>
> --
> With regards,
> Sandeep Kumar Anantapalli,
>
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