Re: [U-Boot-Users] ubi and u-boot

[Jamie Lokier <jamie@shareable.org>]

Josh Boyer wrote:
> > Hamish Moffatt wrote (Message-ID: <20080407073227.GA6317@cloud.net.au>):
> > > Sorry I should've said 512MiB perhaps: 512 megabytes.
> > > UBI attach time appears to be about 6 seconds.
> > 
> > If 6 seconds is as fast as it can be done, annoying but fair enough.
> 
> You should read that thread a bit more carefully.  The scan time is
> highly dependent upon the NAND driver beneath UBI.  For example, a UBI
> scan/attach on a 1GiB device on OLPC was 2 seconds.

Ah, I intended to quote the 2 seconds too but forgot, sorry.  I think
2 seconds per gigabyte is a significant time, too, but not so much.

The followup suggested it was due to the speed of the chip, not so
much the driver.

> > Adding _another_ 6 seconds to the boot time seems a lot to me.
> 
> You mean adding another "X amount of time depending on factors outside
> of UBI's control."

Well, yes, that would be a reason to consider whether doing it is a
good idea :-)

> > I can understand the hesitation, but I think 6 seconds just to find
> > the kernel - especially when doing a 'disk resume' - is quite a lot.
> 
> You should really stop quoting this 6 second number.

Let's call it 2 seconds per gigabyte, then.

> > Note that I haven't tried UBI myself yet.  I'm going on what has been
> > written to the list so far, as quoted above.
> 
> Maybe you should try it :).

I will when good looking figures are being quoted on the list ;-)

-- Jamie