U-boot uImage load speed from SD (on LCDK)

István Gyürki

Hi All,

I'm trying to optimize boot time of my LCDK board based application.

Linux is on SD card, uImage on separate partition and using standard command line to load:

mmc rescan 0
fatls mmc 0:1 /
fatload mmc 0:1 c0700000 uImage
bootm

However, speed of loading uImage is very low, even the trimmed down 1.7MB version of the kernel image takes around 3s. I tested the speed of the SD card in a normal card reader it can read around 18MB/s, and the DAVINCI PSP performance guide (here http://processors.wiki.ti.com/index.php/DaVinci_PSP_03.22.00.06_Device_Driver_Features_and_Performance_Guide) is also listing similarly high values.

Based on this, I'd expect sub-second load times for uImage.

U-boot is the stock version coming with the LCDK board, terminal says:

ver=U-Boot 2010.12 (May 07 2012 - 16:09:45)

Any hints, how to speed up this process?

Thanks,

Istvan

over 12 years ago

0 Raja over 12 years ago

TI__Guru* 81335 points

Hi,

Thanks for the post.

Please refer below wiki links to optimize the boot time optimization.

http://processors.wiki.ti.com/index.php/Optimize_Linux_Boot_Time

http://processors.wiki.ti.com/index.php/Boot_Time_Optimization

0 István Gyürki over 12 years ago in reply to Raja

Intellectual 310 points

Hi Rajasekaran,

Thanks for the links. I'm mostly satisfied with time spent with Linux boot itself, I optimized already a lot there.

The only thing puzzling me is why loading a 1.7MB file from the SD card takes around 3-4 seconds, where I'd expect it to be at least 10x faster even if I'm calculating in some overhead.

Istvan

0 Raja over 12 years ago in reply to István Gyürki

TI__Guru* 81335 points

Hi Istvan,

The benchmark results are measured on top of Linux PSP not on top of u-boot.

The u-boot may not be designed for performance (Interrupt etc)

Thanks.

Processors

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U-boot uImage load speed from SD (on LCDK)