[U-Boot-Users] Boot the kernel from a JFFS2 filesystem

[Wolfgang Denk]

In message <IGEFJKJNHJDCBKALBJLLMEMMFKAA.joakim.tjernlund at lumentis.se> you wrote:
>
> > Well, having to deal a lot with customers who want to  minimize  boot
> > times  I can see the argument that you have an additional memcpy here
> > - but then, when boot time matters, you should not use JFFS2 to store
> > the kernel image in the first place.
> 
> Optimizing crc32 will probably help a bit. I have pushed some optimiziations into

No. We're not talking about optimizing a few percent. When  you  have
to  have  the  application  up and running within 5 or even 3 seconds
after power-on you have to pay some price. You cannot afford  to  use
compression,  and  even  a  highly optimized CRC over an uncompressed
kernel image takes nearly as long as the uncompress would.

I think you cannot beat the speed of loading an  uncompressed  kernel
image  from  flash (raw memory, no filesystem), with CRC verification
turned off. If security plays a role, you  can  (and  will  have  to)
verify the in-flash image later, when you are up and running :-) ]

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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