[Interest] [linux] QtCore behaviour w/o system init

[Mandeep Sandhu]

Actually, I don't k now yet, but right know a good candidate for this

> particular project is the SAMA5D3 by Atmel (the only Cortex A5 on the
> market) [1], other candidates on the radar are TI AM35 (beaglebone) or
> 43 (?) and Freescale i.mx6 to name a few. I have a very, very strong
> power consumption requirement.
>
> I don't have access to SSD but I will likely only have access to "raw"
> NAND flah.
>

Also, choose your FS carefully. UBIFS (fastest, I think) or YAFFS2 are
decently fast, JFFS2 is slow.


>
> >
> > I would try booting a minimal kernel that you compiled yourself ('make
> > xmenuconfig'), compiling Qt statically into your application (This will
> > result in a several MB binary which I would put into your initram fs. I
> > think the most time spent will be just reading the image.
>
> The idea is to get rid of the initram fs, it takes time to the
> bootloader to load it, the XIP kernel (eXecute In Place) is there too to
> help reduce load time, as the bootloader doesn't even have to load the
> kernel.
> I do agree that it will have to be balanced: NAND execution/access time
> (read: read time) vs the speed of loading the same quantity of data from
> NAND to RAM (likely SDDR2, maybe SDDR3) + RAM execution/access time.
>

With XIP you'd normally use a NOR flash because of it's higher read speeds.
You cou8ld also try using a uncompressed kernel image, though at the cost
of size.

Some more info here:
http://elinux.org/Kernel_XIP

Also have a look at the "Boot to Qt" project. One of the hardware used was
a beaglebone:
http://blog.qt.digia.com/blog/2013/08/15/boot-to-qt-on-embedded-android-and-linux-technology-preview-2-released/

HTH,
-mandeep
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