Dear Abu On our board we have a dedicated register to measure the ticks, right from the "POWER key press". This register is incremented 32567 times every second.
We directly read the register with physical address(MMU is not turned on bootloader, during uncompress_kernel MMU& is on but still one on one mapping) values to know the current timing from boot up. I profiled at the places where zImage copying happens & decompress_kernel functions(misc.c) & "restart:" label in head.S. and got the above results. Regards Sandeep. On Thu, Feb 7, 2013 at 1:52 AM, Abu Rasheda <[email protected]> wrote: > On Wed, Feb 6, 2013 at 3:53 AM, sandeep kumar > <[email protected]>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 <[email protected]>wrote: >> >>> Hi Sandeep >>> >>> >>> >>> On Wed, Jan 30, 2013 at 6:35 PM, sandeep kumar < >>> [email protected]> 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, >> >> _______________________________________________ >> Kernelnewbies mailing list >> [email protected] >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >> >> > -- With regards, Sandeep Kumar Anantapalli,
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